Need a PXI-based Test System? | PXI LabVIEW Programming2019-02-21T13:19:04-04:00

LabVIEW PXI Solutions – Need a PXI-based test system?

  • Over 1,500 PXI-based solutions delivered

  • Platinum level National Instruments Alliance Partner, which puts us in the top 2% worldwide

  • One or more: Certified LabVIEW Architect, Certified LabVIEW Developer, Certified TestStand Architect, Certified TestStand Developer

With over 1,500 PXI-based systems under our belt, we’ve utilized PXI for numerous manufacturing test and product validation applications.  The broad range of off-the-shelf expansion cards and processing horsepower make PXI-based test systems a formidable choice for many automated test applications.

Dr. James Campbell
Dr. James CampbellPresident

NI’s PXI platform is great for systems that require the wide range of test instruments that PXI supports, or that need the processing power of a PXI controller. PXI data acquisition hardware is capable of handling 1000s of digital and analog I/O. PXI test systems can process massive amounts of data with the latest CPUs or with some of the largest Xilinx FPGAs.

Viewpoint has used PXI for test applications revolving around:

  • Product validation.

  • Endurance/reliability testing.

  • Manufacturing test.

We’ve utilized a lot of PXI modules, including:

  • Multifunction reconfigurable I/O

  • High-speed serial

  • Digital I/O

  • Digital multimeter (DMM)

  • Multifunction I/O

  • Programmable power supply

  • relay

  • oscilloscope

  • serial interface

  • source measure unit (SMU)

  • vector signal generator

  • signal insertion switch

  • multiplexer switch

  • matrix switch

  • analog output

Need a PXI-based solution? Chat with a PXI Developer.

Whether you’re looking for a turnkey solution or just want some help with a piece of your application, our PXI developers are here to help you.

Want more proof points?  Check out these PXI case studies:

NI FlexRIO-based Custom Test Equipment for High Speed Digitizer sensor

NI FlexRIO-based Custom Test Equipment for High-Speed Digitizer sensor

The initial interface/test system to the DUT was up and running and getting real data from the DUT in ~2 weeks, allowing the customer to maintain a tight development schedule.

Client – A Large Manufacturer

Challenge

Our client was developing an image sensor component and needed to validate the part for a new product line.  They wanted to use as much COTs hardware as possible to start testing as soon as possible.

Solution

The custom product validation test equipment utilizes the NI PXI with FlexRIO  off-the-shelf hardware combined with custom LabVIEW-based software.

Benefits

  • The initial interface/test system to the DUT was up and running and getting real data from the DUT in ~2 weeks, allowing the customer to maintain a tight development schedule.
  • Packet Decode completed at FPGA Level allowed error handling and only pertinent data being saved as needed.
  • Data Manipulation done at FPGA level for unbundling data into correct disk readable format in real-time.
  • All Data captured with TDMS Files to disk enables a higher level of analysis of the data offline.

System Overview

The new PXI-based automated test system utilizes NI’s FlexRIO with NI stock LVDS FAM.

  • Custom VHDL was created to handle the required adjustable delay lines in the data I/O lines and interface to the I/O on the FAM Connector.
  • The VHDL interfaced to LabVIEW FPGA which was utilized to stream the data to disk.
  • Data is stored onto disk during a test and only the payload data from decoding the protocol is saved.
  • The data coming from the UUT is de-packetized and ordered for manipulation downstream.
SOFTWARE FUNCTIONS
Custom FAM VHDL and LabVIEW FPGA interface Development
Custom LVDS Adjustable Delay lines per LVDS Data stream
LVDS Buffering
Generate multiplied Clock from external clock input to latch in data
Source the multiplied clock to Internal LabVIEW FPGA Clock
FIFOs for clock domain crossing and DMA
High-speed data streaming to Disk
LabVIEW RT for example interface to FPGA
GUI
HARDWARE USED
NI FlexRIO
NI FlexRIO FAM – LVDS
NI LVDS to Flying lead cable
NI PXI Chassis and Controller
Yes, I need a FlexRIO-based Custom Test System »

NI FlexRIO enables Device Evaluation & Characterization for high-data-rate sub-system

NI FlexRIO enables Device Evaluation & Characterization for high-data-rate sub-system

100s of man-hours saved in capturing the data.

Client – Automotive Manufacturer

Challenge

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.

Solution

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.

Benefits

  • 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.

System Overview

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.

SOFTWARE FUNCTIONS
Custom FAM VHDL and LabVIEW FPGA interface Development
Aurora 8b/10b de-serialization and clock recovery
LVDS Buffering
Clock to Internal LabVIEW FPGA Clock
FIFOs for clock domain crossing and DMA
High Speed data streaming to Disk
LabVIEW RT for example Interface to FPGA
GUI
HARDWARE USED
NI FlexRIO
NI FlexRIO FAM – LVDS
NI LVDS to Flying lead cable
NI PXI Chassis and Controller
INTERFACES / PROTOCOLS
Aurora 8b/10b
TCP/IP

Custom Test System Using NI PXI for Electrical Test

Custom Test System Using NI PXI for Electrical Test

Updating an obsolete tester that maintains functionality

Client – Medical Device Manufacturer

Challenge

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.

Solution

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.

Benefits

  • Improved maintainability and reliability with updated hardware and software
  • Maintains existing test system functionality to keep certification time down

System Overview

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.

SOFTWARE FUNCTIONS
Read UUT limits from config file
Perform tester self-test
Measure impedance
Power UUT
Pressurize UUT
Measure UUT output
Perform leak down pressure test
PLC interface (for automated tester) for start, done, pass, fail
HARDWARE USED
Custom test fixture (provided by client)
NI PXI
PXI Multifunction I/O Module
PXI Digital I/O Module
PXI Relay Module
PXI Digital Multimeter Module
PXI Switch Matrix Module

*- images are conceptual, not actual

Automated Manufacturing Test System for Electronic Medical Devices

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

Challenge

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.

Solution

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.

Benefits

  • 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.

System Overview

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.

SOFTWARE FUNCTIONS
NI TestStand
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
HARDWARE USED
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
Audio amplifier for speaker tests
INTERFACES / PROTOCOLS
Ethernet

*- images are conceptual, not actual

Yes, I’d like to chat about my test system needs »

Automated Manufacturing Test Systems for Medical Diagnostic Equipment

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

Challenge

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.

Solution

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.

Benefits

  • 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.

System Overview

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.

V&V Effort

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.

SOFTWARE FUNCTIONS
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
HARDWARE USED
PXI chassis and controller
PXI acquisition cards for analog measurements
PXI acquisition cards for digital input and output
CAN card
INTERFACES / PROTOCOLS
Ethernet
CAN

*- images are conceptual, not actual

Yes, I’d like to chat about my test system needs »

Product Validation using LabVIEW RT & LabVIEW FPGA – Electromechanical Actuator Test Stand

Product Validation using LabVIEW RT & LabVIEW FPGA – An electromechanical actuator test stand

Automated testing reduces operator man hours and increases production throughput.

Client – A manufacturer of actuators in the mil-aero industry.

Challenge

New Product Introduction (in this case a new controller and new actuators) drove the need for a new automated electromechanical test stand.

Solution

New NI PXI-based electromechanical test equipment provided automated testing, report generation, and SPC data generation.  The sequencing of the test procedure, reporting, and verifiable results were managed with the StepWise platform.

Benefits

  • Automated testing reduces operator man hours and increases production throughput.
  • Meets strict customer requirements regarding testing and data recording in a verifiable manner.
  • Automated Test Report Generation.
  • Collects data to support SPC (Statistical Process Control).
  • Ability to obtain the internal state of the controller FPGA via the LVDS communication link.

System Overview

Viewpoint developed the software and selected NI data acquisition and control hardware for the test stand.  There are several layers of software functionality.

HOST LABVIEW SOFTWARE LAYER
Test sequencer
Test steps (e.g. Frequency Response, Step Response, Dynamic Stiffness, Fault Response, Power Consumption)
Test Report Generator
GUI
REAL-TIME (RT) LABVIEW SOFTWARE LAYER
Data acquisition
1553 comms
Function generator
Error detection
ESTOP
LABVIEW FPGA SOFTWARE LAYER
Synch data from 3 sources (tester, UUT, external DAQ device)
Stream high-speed data to disk
Stream high-speed data to analog outputs for engineering use
Custom communication protocol used by UUT over LVDS lines
HARDWARE RECOMMENDED
NI PXIe
NI FlexRIO card with LVDS adapter module
Multiple NI R Series cards
High speed, high voltage, isolated analog input cards
INTERFACES / PROTOCOLS
MIL-STD 1553 bus
LVDS
Ethernet
Custom TCP/IP

*- images are conceptual only, not actual

Yes, I need an automated test system »

Creating an N-Up Tester to handle increased production volume demands

Creating an N-Up Tester to handle increased production volume demands

Enhanced throughput offers ROI payback period of less than 1 year

Client

Automotive Components Supplier / Manufacturer

Challenge

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.

Solution

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.

Benefits

  • 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)

System Overview

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.

SOFTWARE FUNCTIONS
Test System GUI
Test sequencer
Startup checker
Test Results Archiver
Yes, I need an N-up tester »

Hidden Factory Assessments Lead to Waste and Cost Reductions

Sharing Business and Test Data Enables Efficiency Improvements

 

Reduce Production Costs by Coordinating Business and Test Data

 

Client: A major manufacturer of aerospace components

Problem Scope

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.

Challenge

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.

Solution

We designed the PXI-based system based on the StepWise 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.

reduce-production-costs-tool-gain-chart

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.

Manufacturing Test – for mission-critical components

PXIe

Manufacturing Test – for mission-critical components

 

Using PXI & LabVIEW RT

Client: A major manufacturer of implantable cardiac and neural stimulators

Challenge

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.

Solution

PXIe

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.

Benefits

  • 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

System Overview

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.

SOFTWARE FUNCTIONS
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.
MAIN HARDWARE COMPONENTS
PXI chassis & controller
PXI DMM
PXI analog input modules
SCXI multiplexing switches
INTERFACES / PROTOCOLS:
Ethernet TCP-IP
CAN
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High-Speed Digital Record and Playback Solution

DRAP-hardware-options

High-Speed Digital Record and Playback Solution

 

At maximum throughput, the systems needed to consume during record and produce during playback about 800 MB/s/slot.

 

Client: A large company involved in C4ISR

Background

A large company involved in C4ISR was developing a system for a new high-speed digital sensor device. Viewpoint was contracted to build a test system used in design validation and ultimately endurance testing of the sensor. Since the sensor was a component of a larger system which was being developed at the same time, another test system was created to simulate the sensor by feeding signals into the system.

Challenge

Both the amount of data and the frequencies of the various digital signals were nearly at the limit of hardware capabilities. At maximum throughput, the systems needed to consume during record and produce during playback about 800 MB/s/slot. The FPGA clock on the FlexRIO had to run up to 300 MHz. The skew between triggers for data transmission needed to be less than 5 ns even between multiple FlexRIO cards even when the parallel data paths has inherent skews associated with the sensor. Finally, the systems needed to handle clocks that might be out-of-phase.

Achieving these requirements required significant engineering design in the face of multiple possible roadblocks, any one of which could have eliminated a successful outcome.

Furthermore, as usual, the development timeline was tight. In this case, it was a very tight 3 months.

Viewpoint’s Solution

To meet the timeline, we had to work in parallel across several fronts:

  • LabVIEW-based application development for both record and playback
  • LabVIEW FPGA development for marshalling data between the controller and DRAM
  • Custom FAM circuit board design and build
  • FlexRIO FPGA CLIP nodes and code for low-level data handling

Technical Highlights

This sensor had several parallel data paths of clock and data lines with clock speeds up to 300 MHz on each path requiring exacting design and build of a custom FlexRIO Adapter Module (FAM) and unique custom CLIP nodes for extending the FlexRIO FPGA capabilities. The FAM also had a special connector for interfacing to the customer’s hardware.

Additional NI hardware and software completed the system components.

LabVIEW Layers

The host application, written in LabVIEW, managed the configuration of the data acquisition and the control of the LabVIEW RT-based FlexRIO systems. The configuration primarily dealt with the number of sensor channels in use, skew settings between digital lines, and other parameters that dealt with the organization of the data passed between the sensor and the FlexRIO.

Two FlexRIO applications were written, one for record and one for playback. Each FlexRIO application was written in LabVIEW, and managed the configuration of the FlexRIO cards and the movement of data between the FlexRIO cards and the RAID drives. Note that Windows supported for the RAID driver. Between 10 and 32 DMA channels were used for streaming, depending on the number of sensor channels being used.

And, each FlexRIO application had an FPGA layer, written in LabVIEW FPGA enhanced with custom CLIP nodes. For the record application, we developed a custom DRAM FIFO on the FPGA to assist with the latencies on the PXIe bus. For the playback application, we were able to stream directly from DRAM.

FlexRIO Considerations

The FlexRIO and stock FAMs from NI were initially considered as candidates for this project. Clearly, working with commercial-off-the-shelf (COTS) components would be most effective. Three options were available at the project start which could accommodate the required clock frequencies, but none offered both the required channel counts and skew/routing limitations. Hence, we had to design a custom FAM. This decision, made before the start of the project, turned out to be wise in hindsight because the parallel development path resulted in some shifts of sensor requirements which could be accommodated with the custom FAM but might have led to a dead-end with a COTS FAM.

FlexRIO CLIP

In LabVIEW FPGA, a CLIP Node is a method to import custom FPGA IP (i.e., code) into a LabVIEW FPGA application. CLIP stands for Component-Level Intellectual Property. We needed to use special Socketed CLIP Nodes (i.e., VHDL that can access FPGA pins) for this project because we could expose additional features of the Xilinx Virtex-5 not exposed in LabVIEW FPGA by accessing Xilinx primitives. Some specific features were:

  • Faster FPGA clocking
  • Additional clocking options
  • Individual clock and skew control
  • Custom PLL de-jitter nodes

Essentially, the FPGA design had a majority of FPGA code developed in LabVIEW FPGA and we used CLIP Nodes for interfacing the signals between the FlexRIO and the FAM.

DRAP-case-study-image

FlexRIO Adapter Module

As mentioned earlier, we had to create a custom FAM because of the need to route high speed signals from customer-specific high density connectors while synchronizing signals across multiple data channels and FPGA modules to within one (300 MHz) clock cycle.

At these high-speeds, the FAM needed careful buffering and impedance matching both on the signals as well internal components on the FAM PCB. At the start of the design, we utilized Mentor Graphics HyperLynx High Speed DDR signaling Simulation software to minimize signal reflections prior to building actual hardware. This step saved countless hours in spinning physical hardware designs.

We designed the FAM to allow channel routing and access to additional clock and trigger pins on the Xilinx chip and PXIe backplane.

Results

The choice to base these digital record and playback systems on NI hardware and software was critical to completing this project. The open architecture in both hardware (custom FAM) and software (CLIP Nodes) enabled us to include some very creative extensions to the base toolset without which the project would not have succeeded in the allotted pressured schedule and on a predetermined budget. We were able to stretch the capabilities of the hardware and software very close to their maximum specifications by combining COTS and custom much more cost effectively than a purely custom design.

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Improving Efficiency in Industrial Manufacturing Test

milling-machine-cropped

Improving Efficiency in Industrial Manufacturing

 

Simplifying Report Generation for High-Mix, Low-Volume Industrial Servo Valve Tests

 

Client: A major industrial servo valve manufacturer

Challenge

A manufacturer of components for both commercial and military aircraft built a large number of different models of servo valves. Some models were made only a few times each year, while other models were made with an order of magnitude higher volume. Each unit underwent rigorous testing during and after assembly.

Our client needed to submit the results of that testing to their customers but since the production and testing of each unit happened in many locations, possibly even around the world, many hours were spent locating the appropriate datasets and assembling the report.

Furthermore, our client wanted to improve their responsiveness to requests from their customers by having rapid retrieval of the test report for any part after it had been delivered into the field.

Solution

Since the test datasets were varied due to the large numbers of different valve models and associated test procedures, a database was created using a platform based on the Resource Description Framework (RDF). An RDF database can accept arbitrary types of data, manage that data through metadata tags, and adjust gracefully to changes in content and shape of the connections between objects in the database.

This adaptability was key to our client being able to leap past some of the issues in standard SQL-based relational databases.

The results from each test run on each part at each (PXI-based) test system were tagged with metadata and pushed into the RDF database. The StepWise platform interfaced to the RDF database by outputting XML content which was scanned by a routine created for the RDF database and converted into the RDF data and links. The part ID was a critical tag since this allowed searching the RDF database for all results associated with that specific part. This database resided on a server at the client’s headquarters and accepted data from worldwide locations.

Once the data for each part was housed in the database, a report could be generated. To accommodate the variety of data in that report, web technology was used to render the report pages based on the types of data entered into the database, as described by the metadata tags. For example, data identified as waveforms could be plotted or listed in tabular format. Having reports rendered based on the data types made it possible to handle adjustments to the types of data measured by the test system.

Results

With the ability to render reports quickly, our client could produce detailed reports for their customers indicating the performance of any specific requested servo valve.

Our client was able to trim the time to create reports to less than 1 day from the previous effort of 3-5 days and with less error.

  • Data are now organized uniformly, simplifying the location of desired information, as compared with files stored on various test PCs and file servers.
  • The client has the ability to generate automatic emails to their customers with the required reports already attached and ready to go.
  • In potential warranty and customer service situations, having the ability to send the customer a report within hours represented great customer service.

All these features are available consistently across worldwide manufacturing facilities, reducing training and maintenance of procedures. And, of course, the reports handle using metric or English units as appropriate for the end customer.

Decreasing Test Time for Aircraft Landing Gear

Decreasing Test Time for Aircraft Landing Gear

Endurance Testing for Aircraft Nose Landing Gear Steering

Client: A major manufacturer of aircraft landing systems

Challenge

A major manufacturer of aircraft landing equipment needed to develop a means of endurance and fatigue testing new designs for aircraft steering. The actuators involved in steering the nose landing gear (NLG) required precise and reliable control through thousands of steering cycles.

Control loops needed to be closed at faster than 1 ms.

Prior systems were handled manually without real-time control and monitoring.

 Solution

Our customer designed and built a test rig to provide the hydraulics and environmental conditions for the endurance testing on the NLG. Viewpoint Systems supplied the electronic data acquisition and control hardware coupled with real-time software to provide the required fast control loops. The configuration and execution of the 1000s of steering cycles were managed by the same data acquisition and control system through a set of configuration screens that allowed specification of turn rates, min/max angles, drive and resistive torque settings, and so on.

  • The various PID control loop configurations were also configurable along with gain scheduling required under different operating conditions.
  • The environmental conditions were supported by controlling a temperature chamber through ramp and soak settings occurring during the steering tests.
  • Measurements on the steering performance were collected from commanded setpoints, sensor readings, and controller outputs during the entire test run.
  • Alarm and fault conditions, such as force exceedance, were monitored continuously during operation so that the system could safely run unattended.

The entire system underwent an extremely rigorous acceptance testing procedure to verify proper and safe operation.

SOFTWARE FUNCTIONS
Arbitrary Load and Position Profiles
Flight Position Control
Load Position/Force Control
Endurance/Flight Schedule Execution
Deterministic RT for DAQ and PID Control
HARDWARE
PXI/SCXI Hybrid RT Chassis
Discrete Pump Skid Interface
Custom Control Panel/Console
INTERFACES
Ethernet TCP/IP
SCXI

Results

Prior to deployment of our system, setup of a test was much more manual and operators needed to be around to monitor operation.

With our new system, complete endurance testing could be specified and executed with minimal supervision. Furthermore, the tight integration of real-time control and coordinated data collection made report creation much simpler than before.

The rigorous acceptance test gave trustworthiness to the data and allowed the design engineers to validate performance more quickly than the prior semi-automatic and manual methods of operation.

Setup of tests has been improved from prior operations. The endurance testing itself operated over a huge number of cycles lasting weeks to months between scheduled lubrication and maintenance.

The deployed system measures performance during the entire testing, even between the scheduled downtime.

Digital Record And Playback – For a RF Receiver

Digital Record And Playback – For a RF Receiver

Collect hours of data at >1 GB/s

Client: A large high-tech R&D-oriented company.

Challenge

  • Record hours of data at >1GB/s
  • Play back digital test patterns for the RF receiver at real-time rates to understand bit-error rates
  • Understand effects of RF chain prior to digitization
  • Allow for platform to assist with algorithm development, debug and optimization

Solution

We utilized off-the-shelf hardware combined with custom software and had a working system after ~7 man-weeks of effort. The DRAP system records and plays back digital data only, with A/D conversion being handled by the DUT. The system was developed on the National Instruments PXI Express platform. A RAID array of disks is used to continuously record data. Data manipulation is performed on a Xilinx Kintex-7 FPGA that forms the basis of a National Instruments High Speed Serial board. The DRAP system is connected to the RF receiver using standard SFP+ connectors. A UI connects to the system locally or over Ethernet to monitor and control DRAP during record/playback. The customer can also control the system via an API so that it can be integrated into a larger test system.

Benefits

  • Allows for repeatable data through the processing chain.
  • Can re-sample data, inject new headers into data packets, and re-pack new data.

System Overview

digital-record-and-playback-RF-sensor-case-study

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