Pump Test Station Used Across Multiple Locations Worldwide
Simplifies gathering test data from multiple plants to perform site-to-site comparisons
Client – Large Pump Manufacturer
Our customer needed an updated test system to replace their obsolete/unmaintainable test systems. It was too hard to gather data from multiple sites located around the world, certain algorithms weren’t standardized, and they didn’t have the ability to utilize the test systems to calculate first-pass yield at each site.
Viewpoint developed a new pump test application that harmonizes the user interface, calculations, and test procedures, resulting in enhanced operational efficiency and tracking of the manufacturing process. Furthermore, it is used in multiple global locations with language localization and support for the varying hardware already in place at each site. The new application deposits all the test data from the various sites into a single database for engineering and manufacturing data analysis at corporate headquarters.
Simplifies gathering test data (for analysis) from multiple plants worldwide to perform site-to-site comparisons.
Enables calculation of first-pass yield for each manufacturing plant.
Standardizes algorithms for pump performance summary data calculation for first-pass yield and site comparison analysis.
Abstracts the hardware to support differences in control and measurement hardware at each site and provides a future path to homogenize hardware installations.
The entire system consists of three main applications:
A database management application to allow the user to update test configurations and to enter and associate new pump serial numbers with specific tests.
A pump test data acquisition application that can run up to 5 different tests simultaneously on the UUT, generating a datafile for each test that is also stored in the database.
An application to generate reports from the information stored in the database to provide to customers when delivering a new pump or after a factory witness test.
Custom Endurance Test System – for a medical device
Increased level of automation allows for multi-day and multi-week test runs
A medical device manufacturer
Our client wanted to improve the endurance testing of an implantable medical device product to help determine the recommended lifetime of the product. An obsolete test system existed, but the client wanted improved performance, UX and configurability. They wanted to just hit the “go” button and let it run for days or weeks. They also needed to be able to have new features added after the first release.
The custom product validation endurance test system utilizes NI cDAQ off-the-shelf hardware combined with custom LabVIEW-based software to provide automated N-up endurance testing of the UUT.
Higher fidelity DAQ
Increased configurability of the system to run tests the way the client wants to
Increased level of automation allows for multi-day and multi-week test runs.
The endurance tester physically stresses the UUT to measure force and eventually breakage events. These events are used to help determine the recommended lifetime of the product. The tester tests multiple UUTs in parallel in order to gather more data faster for statistical validity. The system collects data until all UUTs break or the operator stops the test.
Viewpoint provided the software and advised DAQ hardware selection. The rest of the test system hardware was selected and assembled by the client.
The automated test system applies a varying cyclical force to multiple UUTs while measuring the force applied to the device. The software automates the data acquisition, analysis, load application, and motor during a test. The system measures all forces applied simultaneously while synchronizing that data to a cycle counter. That data is analyzed to determine average, maximum, and minimum force applied to the device over a user configurable number of cycles.
While running there are multiple alarm states that are monitored. When these alarm states occur, a file can be generated to dump a user configurable duration of force measurements to a file. Other alarms generated trigger the system to change a digital output state triggering a text message to be sent to the operators of the system. The system was designed to test for weeks at a time.
NI FlexRIO enables Device Evaluation & Characterization for high-data-rate sub-system
100s of man-hours saved in capturing the data.
Client – Automotive Manufacturer
New product development drove the need for validation of a new sub-system (a RADAR sensor ) for use in a next-gen system in an automobile. They needed a way to evaluate and characterize the performance of the component under various conditions that were not defined in the UUTs specs. They wanted to use as much COTS hardware as possible for this first run testing because of the expense of a custom test solution and the timeline.
The NI FlexRIO-based product validation system utilizes COTS hardware, along with some Viewpoint-developed custom software to allow for evaluation and characterization of the UUT.
The utilization of COTs (vs a custom-built FPGA board) test hardware.
100s of man-hours saved in capturing the data.
Allowed customer to manipulate captured data within the LabVIEW environment for more efficient testing, making changes on the fly.
Error Checking done at the FPGA Level allows for guaranteed valid transfers
Packet Decode completed at FPGA Level allows for real-time de-packetization for use in storing only payload data.
All Data captured with TDMS Files for use in over layering different scenarios.
Scalable to add additional serial data channels allowing for more than one sensor to be captured with a single FlexRIO card.
NI’s FlexRIO with NI’s LVDS FAM was used. The NI flying lead cable was utilized initially to connect to the UUT. On the software side custom VHDL was created to handle the 8b/10b serial stream data and clock recovery. The VHDL interfaced to LabVIEW FPGA which was utilized to stream the data to disk on the PXI-based system.
Custom FAM VHDL and LabVIEW FPGA interface Development
Custom Test System Using NI PXI for Electrical Test
Updating an obsolete tester that maintains functionality
Client – Medical Device Manufacturer
Our client already had a test system in place, but the tester (really two test systems testing two different product variants) was becoming obsolete. The tester was old, hardware was failing, and it was getting harder and harder to keep it reliably running. They wanted a new tester to improve reliability, but maintain the functionality of the existing tester to keep the FDA-mandated verification and validation time to a minimum.
The updated end-of-line manufacturing test system maintains the functionality of the old test systems, but with updated hardware and software. The same software is utilized for both the manual test system update and the automated test system update. Our client deployed 6 manual testers and 1 automated tester.
Improved maintainability and reliability with updated hardware and software
Maintains existing test system functionality to keep certification time down
There were two variants of the new test system. One was for an older product line that utilized manual test, with an operator that connected/disconnected the UUT, and initiated the test. The other was an automated tester, integrated into a manufacturing machine. Both testers utilized custom fixtures (provided by the client), off-the-shelf NI measurement hardware (selected by Viewpoint), and custom test software (developed by Viewpoint). The software is configurable for both the manual test system and the automated test system.
Read UUT limits from config file
Perform tester self-test
Measure UUT output
Perform leak down pressure test
PLC interface (for automated tester) for start, done, pass, fail
Manufacturing Inspection System Uses Machine Vision to verify assembly and labeling
Reducing human error with automated inspection
Client – Automotive Component Manufacturer
Our client already had an end-of-line tester in place. However, preventing incorrect product shipments drove them to add machine vision capabilities to verify that the part being packed is of the correct physical configuration and that the part was labeled correctly. They also wanted a more automated way to track which serial numbers were being shipped.
Viewpoint enhanced the existing end-of-line tester by adding machine vision capabilities to verify correct part assembly and part labeling. This capability also allowed for automated tracking of which parts went into which shipping container.
Automated part assembly verification to reduce human error from manual visual inspection
Automated label verification to reduce the chance of shipping the wrong product
The enhanced system added machine vision-based capabilities to an existing end-of-line manufacturing test system. New hardware (cameras, lighting, fixture) was selected and integrated by the client. Viewpoint developed the image analysis routines using the Cognex In-Sight software. These routines were then downloaded and controlled using LabVIEW software developed by Viewpoint. In addition, the LabVIEW GUI contained the image acquired by the camera and the results of the image analysis. The tester can inspect four different part types.
The software essentially performs the following functions:
Look up the expected characteristics of the part being inspected.
Populate the on-camera In-Sight “spreadsheet” with configuration information used in the image analysis/inspection.
Trigger the image capture and read results from the on-camera spreadsheet.
Use the on-camera image analysis to check a critical angle of the part as the part is set in the nest fixture.
Check the information laser etched on the part and compare the results with what should be on the part (relative to the barcode read in for the lot and the 2D barcode on the part) using the OCR/OCV capabilities of the camera.
Perform other physical part characterization image analyses to verify the part was correctly labeled & assembled.
Look up expected part characteristics
Trigger image capture
Read results of on-camera image analysis
Display image taken by camera and show if test passed or failed
Monitor contiguous part failures & initiate shutdown
Automated Manufacturing Test System for Electronic Medical Devices
Using PXI and LabVIEW for modular testing of over 1,000 different models
Client – a medical device manufacturer and repair depot
Our client manufactures hospital patient pendants used to control bed frame, nurse calling, and TV functions. The company was also growing after adapting a business model of being a repair depot for older designs for their own and the pendants of other manufacturers. As such, their products are very high mix and medium volume.
The basic functions for all these pendant models are closely related, so the client wanted a means to build a single automated test system that could verify functionality for 1000s of models. And, since the products are medical devices, the testers needed to comply to 21 CFR Part 820 and Part 11.
The testers were designed to support the common measurements needed to test the circuitry of the devices as well as the complex signals required to drive TVs and entertainment systems. A test sequence editor was created which allowed the client to create as many test sequences as needed to test each specific pendant model by creating a list from pre-defined basic measurement steps configured for each specific measurement.
For example, each device had a power supply, the voltage of which needed to be tested. To test a specific model, a voltage measurement step was added to the model-specific sequence and configured with the upper and lower measurement limits for the power supply. The complete test sequence was created by adding and configuring other measurements test steps as needed. Each test step could also be configured with switch configurations to connect the measurement equipment, such as a DMM, to the proper pins on the device circuit board.
Using this configuration process, the client was able to support the testing of well over 1000 models without any programming. A separate application was developed to create these test sequences which were saved as XML and fed to the test system for selection and execution.
The test execution was managed by NI TestStand and the pre-defined common test steps were written in LabVIEW. The test sequences and test results were interfaced to the client SQL database which they used in their ERP system. This ERP system used the results produced by the test system to help manage the workflow of production, for example by assuring that all units had passed testing before being shipped. Part 11 compliance was handled through checksums used to check if results had been modified.
Test sequence editor used to develop and maintain tests for 1000s of device models
Enabling our client to create test sequences without programming reduced overall development costs by about 50%.
Test sequences and test results were stored in the client’s ERP SQL-compliant database for integration with manufacturing workflow
Modular and common software developed for the test systems reduced the V&V effort during IQ & OQ by allowing testing of the test execution application separate from the individual test sequences.
The automated test system was able to execute each test sequence in three different modes: engineering, service, and production. Each mode has been specifically designed for various departments throughout the manufacturing floor. Typically, the manufacturing engineer would verify the sequence by executing it in engineering mode. Once the test sequence parameters pass, it was then approved for production testing.
During actual product testing, an approved and digitally-signed test sequence is loaded and executed via the test sequencer, designed for automated production. During execution, test results are displayed to the operator and simultaneously pushed to a database. The automated test system produces a record for each tested device, indicating the disposition of each test step and the overall performance of the device. All result data are digitally signed and protected from tampering.
The architecture of the test system follows a typical client – server model.
All client stations communicate with a central ERP and SQL server and each computer is secured by applying operating system security. The SQL server contains all of the test definitions, device history records and results. Information from it can be queried at any time by quality engineers throughout the organization, assuming they have proper login access. This provides real time status about products ready for shipment. Also, other than the software running on the client stations, no other user has permission to write or modify any information in this database. The client is able to keep the server in a protected area separating it from the manufacturing environment while the client test stations are placed throughout the manufacturing area.
Surprisingly, there were only twelve test steps needed to uniquely configure and be combined to create sequences to test well over 2000 unique models. Test steps are capable of measuring basic resistance, current and voltage parameters as well as perform sound quality measurements and high speed digital waveform analysis. Several tests were designed to be subjective while others are fully automated and test to a specified acceptable tolerance. During configuration, each test step requires the manufacturing engineer to enter expected values and tolerance limits to define pass – fail status. Upon testing, the devices are attached to a generic interface connection box and the test system makes the appropriate connections and measurements.
Low-level measurement drivers to interface to a DMM, signal generator, switches, and data acquisition cards.
Measurement-based test steps
Test sequence execution
Test sequence management
User access management
Test report creation and management
Verification of test sequence content and ability of user to execute
Verification of the content of the test results
NI PXI chassis and controller
NI PXI acquisition cards for analog measurements
NI PXI acquisition cards for digital input and output
NI PXI DMM for precision voltage and resistance measurements
Automated Manufacturing Test Systems for Medical Diagnostic Equipment
Using NI PXI and LabVIEW as a common architecture for multiple test systems testing several subassemblies
Client: a manufacturer of automated blood analysis machines
Our client was embarking on a complete redesign of their flagship automated in-vitro Class 1 blood diagnostic machine. In order to meet schedule goals, the design and build of several automated test systems needed to occur in parallel with the overall machine. In a major design paradigm shift, many components of the machine were being manufactured as modular subassemblies, every one of which was an electro-mechanical device. Thus, multiple testers were required to test each of the specific subassemblies in the machine. And, since this was a medical device, the testers needed to comply to 21 CFR Part 820 and Part 11.
With a looming deadline, the testers needed a common architecture, so that all testers could leverage the development from the others. Since each subassembly could be tested independently of the overall machine prior to final assembly, the design of the testers was based on a common measurement and reporting architecture, written in LabVIEW, that interfaced to the customers Part 11 compliant database for testing procedures and measurement results. Furthermore, procedures and validation checks for calibration of the testers were part of the overall test architecture.
Modularization of the test system architecture aided development and maintenance
Reduced overall development costs due to standardization of test sequence steps and reporting
Both test sequences and test results were stored in a managed database that satisfied 21 CFR Part 11 requirements
Modular and common software developed for the test systems reduced the V&V effort during IQ & OQ.
Since multiple subassemblies were being tested, with one part-specific test system per part, the automated test systems used as much common hardware as possible to simplify the development effort through common hardware drivers and test steps. Measurements were made with PXI equipment. Test steps and the test executive that executed the test sequence(s) were developed using LabVIEW.
The types of test steps required to verify the proper operation of each subassembly were categorized into basic operations, such as voltage reading, pulse counting, temperature reading, and communications with on-board microcontrollers. The specifics of each measurement could be configured for each of these measurement types so that each test step accommodated the needs of the specifics of each subassembly. For example, one subassembly might have needed to run the pulse counting for 2 seconds to accumulate enough pulses for accurate RPM calculation while another subassembly might have only needed 0.5 seconds to accomplish that calculation.
The configuration of a test step algorithm was accomplished via an XML description. The accumulation of these XML descriptions of each test step defined the test sequence run on that specific subassembly.
Test results were associated with these test sequences by completing the entries initially left blank in the test sequence, so that all results were explicitly bound to the test sequence.
The operator user interface distinguished between released and unreleased test sequences. With unreleased test sequences, engineers could try the most recent subassembly designs without needing to wait for final validation. The released sequences were only available to test operators. This login-driven branching was managed using the Windows login, so that the client employees could use their company badge-driven login process. Once logged in, the user would be able to execute the test sequence in automated mode, where all steps happen automatically, or manual mode, where one step could be operated at a time.
Furthermore, the Windows environment was locked down using built-in user account group policies to designate the level at which a user could access Windows or be locked into accessing only the test application.
During the V&V effort, each test sequence was verified for expected operation, against both known good and bad parts. Once verified, the sequence was validated against the requirements and, when assured to be as expected, a checksum was applied to the resulting XML test sequence file and all was saved in a Part 11 compliant database. Upon retrieval, when ready to run a test, the sequence was checked against this checksum to assure that a sequence had not been tampered.
Test results, saved as XML in the same file format as the test sequence, were also surrounded by a checksum to verify that no tampering had occurred.
The IQ/OQ efforts were handled in a traditional manner with the client developing the IQ/OQ documentation, with our assistance, and then executing these procedures, again with our assistance.
Low-level measurement drivers
Measurement-based test steps
Test sequence execution
Test sequence management
User access management
Test report creation and management
Verification of test sequence content and ability of user to execute
Verification of the content of the test results
PXI chassis and controller
PXI acquisition cards for analog measurements
PXI acquisition cards for digital input and output
Our client was already doing validation, but it was manual, and the client’s customer started requesting faster turnaround of results. Their customer was also requesting data to be sent with the results. Our client chose to automate the validation process to enhance their productivity.
Logs errors during the test (e.g., for continuous monitoring tests, logging the number of instances of when a UUT’s LIN (Local Interconnect Network) response deviates from a static, current draw outside of limits)
Capable of testing a large variety of product lines
Logs pertinent data to a database for post-test analysis/inclusion into reports
The UUT is an electro-mechanical part that falls under a variety of different product lines. As such, the client had a couple variants of the tester, based on the communication needs of the UUT. A total of more than a dozen testers were deployed. The functionality of the tester evolved over time, specifically modifying software to make the tests faster / decrease cycle time.
Extensive diagnostic/manual operation of system for debug of software and electrical connections between the UUT and the test stand/tooling.
Product-specific software components to operate unique products.
Execute mechanical endurance tests.
Execute environmental endurance tests.
Database output containing results from every test cycle (either mechanical cycles or time depending on test being run).
The client already had a test system in place, but it was old and was becoming unmaintainable. Increasing demands from the test engineers and the old software architecture not lending itself to clean implementation of these new features (new sequencer capabilities and ECU CAN communication) drove the need for a rewrite of the software application.
The updated product validation tester supports product validation of the UUT by automating long tests (sometimes a week or more) providing the desired set point control, allowing the client to prove more obviously that their part met the stated specification. Viewpoint developed the software and the client selected the hardware.
Automate long duration tests
Improved operator UX by making controls and indicators more intuitive to the user as well as providing additional capability within one application.
Acquire ECU data along with measured UUT data to allow for engineering performance characterization analysis
Playback utility enables the Test Engineer to quickly view collected data to chart out a path forward for further testing.
Automate a Design of Experiments matrix of conditions, through new sequencer capabilities, to more quickly arrive at product characterization parameters.
All collected signals are now housed in one TDMS file instead of multiple files from different applications.
The UUT is a complete engine with a focus on one of the mechanical subsystems. Data is collected on over 100 channels, measuring temperature, vibration, strain, RPM, position and pressure. Engine management data (e.g., component location, pressures, engine speed, and status flags) is collected via CAN. The engine speed is set via an analog output, and subsystem setpoints are sent to the ECU via CAN. SCXI still used on some of the old test stands, but is being phased out in favor of cDAQ. The test system software was developed in LabVIEW.
Synchronizing data from multiple data logging instruments
Client – Manufacturer of commercial equipment
The client already had a method in place to log data needed for validation testing. However, this data was acquired from multiple independent data logging applications. They needed something to aggregate the data and align/synchronize the data across multiple instruments.
Viewpoint developed a LabVIEW-based product validation solution that continued to utilize the existing data logging hardware, but uses software to aggregate & synchronize the data from multiple sources. This simplifies post-processing.
Synchronized & aggregated data from multiple instruments
Ability to add capability for new instruments later on
Real time graphing of all channels
Channel averaging across multiple instruments
Ability to save data acquisition configurations for future use
Faster channel configuration than current data logging applications
The data logging software unifies the collection of data for a particular validation test. The software configures each instrument, kicks them off, logs the data to a TDMS file, and also graphs data and displays real-time values.
An automated system permits faster validation, unattended test, an increase in throughput, and can free up resources for other tasks during the weeks long endurance test.
Client – A manufacturer of aircraft components in the mil-aero industry
New product development drove the need for a new endurance test system for product validation. The old systems were not designed to test the newly designed part (aircraft actuators), and the company didn’t have the time or resources to reconfigure existing systems to perform the testing required.
The new PXI-based endurance test system provides automated electromechanical testing, full data recording, report generation and a diagnostic panel for intelligent debug. Viewpoint selected the NI equipment, while the test consoles, and other components were selected and fabricated by the customer.
An automated system permits faster validation, unattended test, an increase in throughput, and can free up resources for other tasks during the weeks long endurance test.
Full data recording with a data viewer enables post analysis, which provides the ability to review and analyze raw signals captured during execution. Channel examples are actuator LVDT position, load, current, and encoder actuator position.
Summary report capability allows the customer to document the amount of testing completed against the full endurance test schedules.
A manual diagnostic operational panel provides the ability to verify particular DUT functionality or components without running an entire schedule.
Systems can be paused and restarted to allow for “scheduled maintenance” of the DUT such as inspections, lubrication, etc.
The PXI-based endurance test system enables data collection, deterministic PID Loop Control, emergency shutdown and a diagnostic panel for manual test and debug operation. The system runs endurance test schedules, that are defined as a recipe for test execution. These schedules, which are customer-defined and DUT-specific, are designed to simulate the actual conditions the DUT would see in real world application as closely as possible. LabVIEW-RT was used for the deterministic looping for Closed Loop Control of Actuator Position and Load Control. LVDT demodulation was performed on a PXI FPGA card programmed with LabVIEW FPGA.
Full Data Collection for Real-Time and Post Analysis
Deterministic PID Loop Control
Diagnostics Panel for Manual Test and Debug
Endurance Test Schedule Execution
Hydraulic Control Panel for Source & Load PSI Control
Ability to run tests unattended and overnight reduces operator labor and compresses test schedules
Client – Major Aerospace Component Supplier / Manufacturer
The client had an older VB & PLC-based test system in place already, but it was obsolete. A new endurance test system needed to be developed to validate prototyped components (in this case, aircraft & aerospace bearings). Many of the prototypes are one-off, so it was important that the test system not destroy the component.
A new endurance test system was developed to validate prototyped components. The test system can be configured for automatic shutdowns so as not to destroy the component under test in the event of unexpected performance of electro-mechanical subsystem components. The updated endurance tester supports product validation by allowing the product to run under various test conditions (e.g. speed, load, oil flow, temperature) and collecting data for analysis.
Viewpoint developed the software and selected the NI hardware (other hardware was selected by the client).
Ability to run tests unattended and overnight eases operator labor and compresses test schedules
Data collection allows for offline engineering analysis
Automatic shutdowns reduce destruction of the prototype component under test
The updated cRIO-based endurance tester incorporates configurable profiles, data logging, and automatic shutdown to allow for safer extended validation testing. LabVIEW FPGA and LabVIEW RT were used together to interface with the test hardware sensors and controls. LabVIEW as used create the HMI for the test system.
Closed loop control of bearing test oil flow
Axial load control
Driver for Emerson VFD
E-Stop and safety management (shutdowns based on alarm limits)
Data collection – temperature, pressure, flow, vibration, frequency
Multiple International Deployments Helps Prove Product Meets Spec.
Each endurance test can run upwards of 6 months.
Client: Major Automotive Component Supplier
A new endurance test system was developed to give more precision in the control setpoint. This additional precision enabled potential clients to review the product performance in real-life situations. Each endurance test can run upwards of 6 months.
The updated endurance tester supports product validation by providing the desired parameter control method, allowing the client to prove more obviously that their part met the stated specification.
Viewpoint developed the software and selected the NI hardware for the first unit. The client is now deploying copies of this system to multiple international manufacturing plants.
Able to prove meeting a particular product specification of interest
Closed loop parameter control
Emergency shutdown functionality
The cRIO-based endurance tester provides closed loop control, data collection, and alarming with controlled and emergency shutdown functions. The operator can manually configure a test or load a saved configuration. After a manual operator check to make sure the setup is operating correctly, a successful test will run its full duration and stop on its own.
Creating an N-Up Tester to handle increased production volume demands
Enhanced throughput offers ROI payback period of less than 1 year
Automotive Components Supplier / Manufacturer
The company makes automotive components in very large volume, several part models each at more than 1 million per year.
The client’s primary concern was conserving floor space. They were completely out of spare manufacturing space.
Viewpoint created an N-up NI PXI-based Manufacturing Test System. In this case, N=6 because analysis showed that a 6-up electronic part tester allowed the test operator to cover the test time with the load/unload time.
At the high volumes needed, the client needed to parallelize as much as possible. The cost of 6 sets of test equipment and device sockets was less important than speed. Using the equation:
ProfitPerUnit x NumberAdditionalPartsPerYearAfterParallelizing > CostOfTestEquipment,
being able to completely parallelize made the number of extra units per year large enough that the payback time for completely duplicating the measurement instrumentation for each UUT socket was less than about 1 year.
Paid for itself in less than 1 year by the enhanced throughput.
This approach consumed about 20% the floor space that would have been used for duplicating the test system 5 more times (for a total of 6 testers)
Viewpoint developed an NI TestStand application that ran 6 instances of the test sequence independently of each other utilizing the duplicated PXI-based test equipment. The common parts of the overall master sequence were:
Startup check for the entire test stand
Shutdown of the entire test stand
Archiving the test results into the database
Part handling was managed by a PLC and robot which delivered the parts from a tray into the UUT sockets. Digital bits were used for signaling the test sequence which parts were present in their sockets and ready to test.
Reduced test time across several products by an average of ~25% and reduced time to create paperwork by ~3x
Manufacturer of high-voltage power supplies
The client already had an existing manufacturing test system in place. They wanted Viewpoint to enhance the tester due to an increase in production volume demand. Viewpoint reviewed the existing test system and noted 3 areas for improvement:
Automation available in the measurement instruments – most of the test equipment was automatable, via some combination of serial, GPIB, or Ethernet interfaces. Furthermore, some equipment, such as an oscilloscope, had the ability to store and recall setup configurations. The test operators already used these configurations to decrease setup time for the next test step. Most test equipment did not have automated setup.
Operator time spent on each test step – the client had been through a Lean assessment and had already done a good job of timing operations. However, we specifically noted that the operator was manually connecting to the test points and manually transcribing to paper the measurement results from instrument displays.
Automating the connections – many types of product models were being tested at this test system. Connecting the test equipment to all sorts of products would require either 1) many types of test harnesses and connectors or 2) a redesign of the products to make test connections simpler and quicker.
The enhanced automated test system included automation of instrumentation interfaces, a test executive to run the test sequences, automated test report generation, and automated test data archiving for the electronic UUT.
Reduced total test time across several products by an average of ~25%.
Time to create paperwork was reduced by ~2/3 due to automated data collection.
The enhanced test system included the following updates:
Test sequence automation
Automated test report generation
Automated test data archiving
Automation of instrumentation interfaces
Configurable automated test steps associated with each type of measurement instrument. The test operators would create a sequence of steps to setup each instrument and record the resulting measurement. The sequence of steps could be saved and recalled for each product to be tested, so the instruments could be used automatically.
New programmable meter – integrated the new DMM meter with a programmable interface to replace the one that was not automatable.
Foot switch integration – Since the connections to the test points were manual, a foot switch allowed the operator to take the measurement and advance to the next step.
The StepWise test executive platform managed the multiple test procedures created for the different products. StepWise also handled creation of HTML reports for every part tested.
It did not provide ability for unattended operation
The thermal control had to be set manually
They wanted to do less manual review of the data
The client develops mission-critical products, so there’s a desire to reduce manual operations because they have to explain any anomalies, and manual operations are typically more error-prone. They needed repeatable results that they could trust.
Viewpoint developed a new test system that utilized new hardware and software, augmented by existing low level hardware and firmware. The test system was developed to perform both functional test for production and environmental testing, and was designed to handle up to 4 DUTs at once. The test system utilizes the StepWise test executive software with custom test steps, which allowed the client to create their own highly configurable test sequences. The system was developed in two phases, with the second phase adding support for a FPGA expansion backplane (NI CompactRIO chassis) in order to provide future capability for bringing some of the microcontroller sequence activity into the NI space. In addition, the previous version had a mix of serial, TTL, and USB instrumentation, which was not as robust as Ethernet based instrumentation. Phase II involved upgrading to all Ethernet based instrumentation, and did away with the original test system’s many manual toggle switches that could be used instead of the programmable mode through the SW.
~40% test time reduction per unit
~25% reduction in anomalies that needed to be justified
Our client produces welding consumables. These products are inspected for continuous improvement of product performance. Our client wanted to standardize their data collection method to improve product quality and utilize SPC (statistical process control) across multiple international manufacturing facilities.
The solution is a relatively straightforward data acquisition system measuring force, vibration and voltage for comparison across multiple international manufacturing facilities to support continuous improvement of product performance.
Standardization of data collection across multiple manufacturing sites
Ability to check product performance tolerances, which could trigger root cause analysis
Ability to analyze data across product runs and across sites for SPC
The system utilizes off-the-shelf data acquisition hardware from National Instruments along with custom LabVIEW code to perform force and vibration measurement and basic calculations such as RMS Min and Max. Each test generates an MS Word file showing summary data as well as graphs of each attribute over time. In addition, the program creates (and automatically archives) a complete data set of all data recorded during the trial and finally adds a line with all the summary results and comments to a Master log file. This Master log file can then be sorted by date, wire type, diameter, or any other input for analysis.
Our client had an old manufacturing inspection system (really two systems: one inspection system and an assembly/inspection system) that would no longer be supported by IT and was going to be removed from the network. They needed the operating system updated, so they decided to take this as an opportunity to port the old code from VB to C#.NET, as well as update some hardware.
As migration projects often do, this effort began by working with the client to solidify requirements, followed by a reverse engineering effort to understand the old system to try to make it match the new system as much as possible.
The updated manufacturing inspection system (one inspection system and an assembly/inspection system) included a new operating system, ported code, new motion control software, new machine vision software, and a new GUI.
OS Update – Updated operating system that is supported by the IT department and is less of a security risk
Software Porting – Ported software to more maintainable language
Measurement Accuracy – Increased inspection measurement accuracy for sub-set of measurements
New GUI – improved operator user experience by improving readability, reducing # of required button clicks, and adding auto scroll functionality
Report Generation – maintained existing format to interface with customer database
The device under inspection is essentially an image sensor array used for scanning images in high end commercial-grade scanning printers. The inspection system utilizes machine vision and precision motion control to verify the location & orientation of several parts, with measurement accuracy measured in microns.
Sharing Business and Test Data Enables Efficiency Improvements
Reduce Production Costs by Coordinating Business and Test Data
Client: A major manufacturer of aerospace components
Many companies operate in a high-mix, low-volume manufacturing environment. In these situations, production of such parts is often complex, with long assembly and test procedures describing the process to make and verify the part. Discussions of automating any part of these processes are often dismissed because an automated test system is thought to be expensive, especially when each part is thought to need a unique test system.
Our client wanted to improve their capability to manage the assembly procedures and get clarity on the status of any parts, whether partially or fully assembled. The existing situation had data manually-entered into a database form or even handwritten data that needed to be transcribed into a database. Often the database was local to the assembly cell. The chance for error was significant and the lag between data collection and updating the database was often days. When questions arose about the status of a particular unit, many hours could be spent in locating and evaluating the associated forms and paperwork.
The steps needed to achieve these goals were clear: automate the collection data on each part while being assembled so that those results would appear in a business-level database which would give a plant-wide view of the status of all the parts in progress.
Thus, this project needed to allow read/write access to sections of the Manufacturing Enterprise System (MES) database so that information about a part being assembled could be obtained automatically and results could be submitted to that MES database automatically.
We designed the PXI-based system based on the StepWise test executive platform to automate the assembly and testing. This platform enables two significant changes. These changes were made at each assembly cell by having the operator use a test PC and perhaps some measurement equipment as appropriate for the part(s) being assembled at that cell.
First, we replaced all the printed assembly procedures with electronic records so that any operator could review the latest version of the work instructions on a computer screen. This approach helped with version control, especially important since the client had various model revisions that came through the factor for rework, each with slightly different versions of assembly instructions.
Second, we displayed those electronically documented work procedures as steps in a test executive, allowing the results of each step in the assembly procedure to be captured electronically. When an assembly step was purely manual with no measurements, the fact that step was completed would be recorded, along with information such as the name of the operator performing the step, the duration that the step took, and so on. When a step required a measurement to be made, such as a functionality verification or a calibration result, the measurement would be collected. If the equipment making that measurement could be automated, we would collect that data automatically, and not require the operator to type the result into a computer form.
The outcome of this effort has enabled the client to get a snapshot of the status of parts in assembly, i.e., Works in Progress (WIP), quickly and accurately.
After these changes were made, many additional capabilities are now available with the advent of purpose-built queries into the appropriate MES database tables. The table below shows the overall efficiency gains achieved.
The key is the combination of the electronic test results obtained at the test equipment with information on work orders and manufacturing flow held in the various tables in the business MES database. This improvement happens even with manual or semi-automated test systems, and does not require a completely automated assembly and test system. Thus, the cost of the test system is much less than usually expected and, hence, the benefits are more easily cost-justified.
Designing an Automated Fuel Cell Validation Test Stand
Verifying a New Fuel Cell Design Through Automated Operation
Client: A major automotive manufacturer
Micro Instrument, an automation vendor that builds test and validation stands, has extensive experience with programmable logic controllers (PLCs) and stand-alone controllers for controlling repetitive motion, safeties, and other “environmental” parameters such as pressure and temperature. The company typically uses PLCs to reliably deliver discrete I/O control and standard PID loop control.
However, Micro Instrument’s customer, a major automotive company, was interested in investigating fuel cells as a power source and they needed to run these fuel cells under a wide range of conditions for extended durations, for both design validation testing and durability testing purposes. Furthermore, the client wanted to implement more advanced control algorithms than simple PID.
The customer knew they needed control loops that predicted system response so we could eliminate overshoot and/or achieve a faster approach to a setpoint. But, because the customer did not know in advance exactly what such “smart” controls would entail, it was beneficial to have the full power of LabVIEW to develop such controls. Providing this functionality with a PLC would be cumbersome, if not impossible.
The customer had some Compact FieldPoint which they wanted to use for this project, so we needed to ensure that this equipment would be sufficient to deliver the required control performance and tolerances. Also, the system needed to conduct PID control in two forms – PWM and continuous control. Importantly, this Fieldpoint hardware had a real-time controller running LabVIEW Real-Time.
We developed a flexible control environment using NI Compact FieldPoint and LabVIEW Real-Time to meet the customer’s system control demands. For example, to predict system response, we programmed the Compact FieldPoint to run control loops that were aware of imminent system-state changes and changed their control schemes accordingly.
As with most validation test systems, we needed to monitor conditions for safety. New product designs are often operated near the edges of safe operation in order for the designer to understand how the product performs in extreme conditions. For this fuel cell application, destructive over-heating and over-pressure could occur. Both digital and analog signals were watched in real-time to assure operation within reasonable bounds and allow a safe shutdown if the fuel cell ran into out-of-bound conditions.
The application used the following independent parallel loops:
Seven for PWM-based temperatures control
Two for continuous pressure monitoring
Four for solenoid and sensor monitoring and control
15 safety loops
Data collected during the validation tests were saved to a local PC for later performance analysis and anomaly detection.
The combination of Compact FieldPoint with LabVIEW Real-Time enabled the customer to run the required custom control algorithms and it surpassed the capabilities offered by standard PLCs.
Client: A major manufacturer of data-critical three-phase uninterruptable power supplies
A major manufacturer of very large three-phase uninterruptible power supplies (UPSs) needed better measurement, analysis, and report generation capabilities. Their clients used these UPSs on mission critical equipment, such as data warehouse server farms, communications equipment, and so one. Existing testing procedures used equipment that did not allow for complete simultaneous coverage of all sections of a UPS unit, from input to output. Our client wanted a better understanding of the signals on each of the three phases at various locations within the UPS, especially when power sources were switched or faults were induced.
Also, in the prior test procedure, factory acceptance reports were manually assembled for our client’s end-customers, delaying the final sign-off. Finally, since the end-customer might want to run a specially configured test or run a series of tests in a different sequence than some other end-customer, our client wanted to be able to rerun certain types of tests or run tests in a customer-specific order. Thus, the test sequencing needed to be flexible and editable, possibly on the fly.
Finally, synchronization between the data collection on all signals was critical to assess functionality, since all 3-phases of the UPS output needed to be in the proper timing relationship.
At a high-level, the majority of testing a UPS relies on knowing the reaction of the UPS to changes on the input side (such as a grid power outage) and changes on the output side (such as an immediate heavy load). Thus, many of the tests performed on a UPS deal with power quality measurements, such as defined by IEEE 519 or IEC 61000 series standards, which cover both continuous and transient operation. The StepWise test execution platform was utilized to allow the customer to develop arbitrary test sequences using the application specific test steps developed for the program.
Our solution used a cRIO to measure both current and voltage from each leg of the 3-phase power (and neutral) by using appropriate cSeries modules connected to various voltage and current test points within the UPS. The cRIO had enough slots to allow a single cRIO to measure a single UPS.
Assessment of continuous operation mainly reviewed the UPS output power quality. Here, it was important to know the amplitude and phase of each leg of the 3-phase power. Synchronous data acquisition between all voltages and current channels was needed for proper timing alignment of collected data points.
Assessment of transient operation was often a review of power ripple and recovery time. For example, in the event of grid power loss, a UPS would switch over to backup power, with the result being a small transient created on the output a UPS. Again, the voltages and currents needed to be collected synchronously to assure that event timing was aligned.
For increased power capacity, the UPSs could be connected in parallel. When ganged together, the continuous and transient behavior of each UPS needed to be compared to the others, in order to capture the behavior of the entire combined system. Consequently, each cRIO (one per UPS) had to share a clock to enable synchronous data collection across all cRIOs. A timing and synchronization module was placed into each cRIO chassis with one cRIO acting as the master clock source and the others being slaved to that clock.
The overall test system architecture has a master PC communicating with each cRIO. Each cRIO was placed in certain activity states by the master PC, such as “arm for measurement”, “transfer collected data”, and “respond with system health”. This arrangement enables the number of cRIO to shrink or grow depending on the number of UPSs being testing in parallel.
The test system connected the timing module in each cRIO in a daisy-chained configuration, leading to data sampling synchronization error of less than 100 ns between all cRIOs, which translates to about +/-0.001 degree phase error for 60 Hz power signals. This timing synchronization was more than sufficient to analyze the collected waveform data for power quality and transient structure.
LabVIEW was used to create various configurable test steps that could be executed in random order as well as in an automated sequential manner. Our client was thus able to test a UPS in a predefined manner as well as react rapidly to queries from their customer when they were viewing a factory run-off test. For example, the customer might ask to re-run the same test several times in a row to validate consistent responses.
Each type of test included automated analysis routines that numerically calculated the relevant parameters against which the UPS was being checked. Not only was this automated calculation faster, but it reduced mistakes and improved reproducibility as compared to the previous post-testing partially manual calculations.
Data from all tests, even repeated ones, on a given UPS were archived for quality control purposes and made a part of the device history for that UPS.
Finally, the report generation capability built into this test system was far superior to the previous methodology by allowing our client to hand their customer a professional report package practically immediately the testing was complete. Customer satisfaction was improved substantially with this state-of-the-art test system.
Client: A major manufacturer of implantable cardiac and neural stimulators
Our client needed several extremely reliable test systems to test the batteries that power their implantable medical devices. These new test systems were needed for two main reasons. First, the needed to upgrade existing obsolete test equipment, based on antiquated hardware and software. Second, new battery designs could not be tested on the old equipment.
A critical aspect of the new test system was the need to detect any excessive charge being extracted from the battery, thus rendering it unsuitable for surgical implantation. Thus, the test system needed to monitor the total energy withdrawn from a battery during testing to assure that it never exceeded a certain limit while also offering precise control of the type of pulses being drained from a battery.
All test results had to be stored in a database in order to maintain device history for each battery manufactured for archiving, quality control, and process improvements.
The updated manufacturing test system is PXI-based along with a custom micro-controller-based circuit board for some low-level control. Each PXI controller communicated to the microcontroller (uC) on the custom PCB via CAN. The uC controlled the current drain from the battery while monitoring actual current and voltage from the battery at over 1000 samples per second using a precision 6.5 digit PXI DMM. Additionally, each PXI chassis was used to test many hundreds of batteries. Signal connections were handled by several switch multiplexers. Overall control of all the PXI testers was managed by a host PC connected to the PXI controller.
Reduced test system cost vs complete COTS solution with combo LabVIEW RT on PXI and firmware on microcontroller-based custom circuit board
Enabled tight control of DUT operation on controller with microsecond level responsiveness while being supervised by higher-level PXI RT
Quick-reaction test abort capability
Test results stored to database for archiving, quality control, and process improvements
In a simplified view, the testing proceeded by pulsing the battery with a series of different durations and varying amperages. The exact sequence of this pulsing is unique for each DUT model. Measurements were made using a PXI filled with various NI boards such as DMMs, for accuracy, and data acquisition cards, for general purpose use.
Additionally, the pulsing amperage levels needed to be tightly controlled in order to know that the tests have been performed properly. Thus, a real-time amperage control scheme had to be implemented to maintain the level requested for the pulse. We chose to accomplish this control via an analog control circuit developed using a custom Viewpoint-developed circuit board. This board was controlled via a Microchip PIC microprocessor. The LabVIEW RT application communicated with the microcontroller to setup the pulsing sequence and coordinate the start and stop of the pulsing and the NI acquisition hardware.
This custom circuitry also reduced the overall cost of the test system by about 40%.
The engineering time to design this custom circuitry was more than offset by the reduction in material costs because more than 10 test systems were deployed, allowing the non-recurring engineering effort to be shared between many systems.
When no critical issues were detected, the waveforms acquired by the PXI system were stored and then analyzed to determine the viability of the DUT. The pass/fail disposition, the waveforms, the total energy consumed, and other test results were then passed along to a master PC that managed all these results in a database for archiving, quality control, and process improvements, each set of results being tied to the unique unit serial number.
The test systems provided reliable operation for testing the large annual production volumes of the mission-critical DUTs.
LabVIEW RT – for managing the microcontroller functions and overall data collection and safety monitoring
Microcontroller application – to provide precision pulsing of the batteries
Communicate to the host PC – to both receive pulsing instructions and configurations and to return pulse waveforms for each battery tested.
Monitoring of Testing Inside Environmental Chambers
Our customer required a system that would replace manual charting of tests performed inside various environmental chambers.
Viewpoint designed an automated solution which notifies the technician when the test chamber requires attention and reports chamber utilization for planning and scheduling purposes.
This application was designed for a group that provides long-term thermal and environmental testing to a large number of internal customers at its facility. The group is responsible for approximately 80 environmental chambers which are used for a variety of tests for electronic circuit boards and modules.
These tests typically last between 100 and 4000 hours, with the environmental chambers cycling temperatures according to an externally programmed profile. This system was developed to automatically monitor and provide oversight to the various test chambers under the department’s control.
On an individual chamber basis, the system can verify that the chamber is performing to the test expectations, provide an audit mechanism and generate alarms when the chamber is not operating correctly. The software also is flexible enough to add and edit individual chambers and the tests inside them. The data collected is compared to set limits and, where appropriate, alarms are generated and events are logged to keep a history of what occurred during a test. The test system is capable of running many tests simultaneously.
The system is scalable and more thermal chambers can be added as needed. The operator can view the status of any given test by selecting the test to be viewed and observing the trend. The server software running on the server PC is tolerant of user logins and logoffs as it is running as an Windows service.
The software was written in LabVIEW as a client/server style application. Using LabVIEW and a small stub of “C” code, the server portion of the software was built into a Windows Service. There is no interface to the server other than the client. The client uses the LabVIEW VI Server technology to communicate with the server. This configuration allows the technicians to check the status of any test from their desk or a remote location.
Test configuration allows the operator to be notified when alarm conditions occur or for a regularly scheduled check of the chamber. The system notifies the operator by sending an email and/or by sending a message to their pager.
All test status information is persistent in an MS Access database so if a power failure occurs, or the system goes down, the tests in progress are not lost. When the system is powered up again, the system will restart any tests that were in progress. Two days of history data is kept in memory for each test so trends can be identified.
The system can generate a number of reports, such as job status, journal events, chamber status, completed test results, and chamber utilization. For each type of report, the technicians can pick from a list of criteria to filter the requested information.