Using a portable PC as test equipment

Portable PC test equipment

The traditional test equipment manufacturers don’t like to admit it – but a properly configured portable computer can be a first rate test and measurement platform.  The flexibility of plug in cards, and the software suites that can combine readings into true analysis can make a portable PC the ideal solution for diagnostics, pass/fail, long term logging and system configuration and calibration devices.

Rugged Military Computer with removable Drives

Systems that require stimulation or a serial data feed to emulate real world scenarios are particularly suited to a PC-based test equipment solution.

So what makes a good portable computer platform?  Primarily it comes down to expansion slots.  While there is plenty of bandwidth available through USB-C and Thunderbolt, there are not many companies manufacturing test equipment cards using those interfaces.  So that means most modern Laptops are unsuitable in two ways: Expansion and Ruggedness.

Test & Measurement

The traditional test & measurement companies (Aeroflex, Anritsu, Bird, FlukeKeysight, Rohde and Schwarz, Tektronix, Yokogawa), make excellent oscilloscopes, function generators and DVM’s etc.  But connecting them all together to make a test suite has always been problematic.  Often, in order to actually get the system to work, it is best to stick to one manufacturer.  Even then you end up with an expensive, fairly fragile, rack full of test equipment connected together using often out of date busses.  Of course there are areas that are not really suitable for PC based systems – Vector Signal Analyzers, and Network Analyzers (not to be confused with PC network sniffers) and frequency agile test sets are unsuited to the somewhat noisy (electronically) interior of a portable computer.  There is a reason that these companies are at the bleeding edge of technology and can sell products for $150K+ that will be useless in a three or four years.

Expansion slots used to create test equipment
Expansion slots

Side view of FlexPAC-III-24

But say your needs aren’t “what is the exact current coming out of this port?” but more “Is the current coming out of this port in range?”  What happens when we stress the system?  A combination of signal generation and data acquisition and some simple coding and you have a custom test system.

These systems are best housed in a rugged portable computer with expansion slots.  Typical modern configurations include a motherboard wit PCIe expansion slots.  An i7 or Intel Xeon processor and SSD storage are now standard.  If data analysis and presentation are part of the task, multi-screen portables are now available – see FlexPAC-III and MilPAC-III

Portable computer MilPAC C4ISR

The most commonly used graphical programming language is National Instruments Labview.  An open source alternative is MyOpenLab. Alternatively you can write in Python and use DAQ libraries from the card manufacturers.

Examples of interface cards:

1553

 PCIE-1553 Card

Abaco systems 1553

Abaco Systems RPCIE-1553 is the latest generation of performance and flexibility for MIL-STD-1553 A/B Notice II on a native PCI Express module. Available in -40°C to +70°C temperature with one, two or four dual-redundant channels, the RPCIE-1553 includes advanced API (Application Programming Interface) software that reduces application development time.

DDC AceExtreme

PCIe 1553 DDC Card

The combination of 1553 with digital and avionics Discrete I/Os offers flexibility that makes the PCI Express Card ideal for most test applications. DDC’s common test/embedded software API increases productivity, allowing your test and embedded designs to be generated from a common source.

  • Save Time and Reduce Costs:
    • Common Software API for Test/Embedded Boards and Components
    • Program in Minutes with Automated Source Code Generation
    • Test and Simulation Toolkit for Advanced Testing
    • On-Board Programmable Coupling/Termination Reduces Cable Setup Time
  • Enhanced Performance
    • On-Board DMA Engine for Low CPU Utilization
    • Bridgeless PCI-E Design Reduces Access Time
    • MSI Interrupts Reduce Interrupt Latency
    • (x1) PCIe = Flexibility

1394 PCIe S800 Optical

PCIe 1394 optical interface from DAP

The PCIe042b is an innovative interface card that addresses the need for 800Mbps data transfer rates over multiple bus interfaces. It allows for one standard 1394 copper as well as two glass optical fiber (GOF) connections. These Fiber connections support both the S800 transmission rates as well as long-haul distances (up to 100m) over LC Duplex 50/125um multi-modes optical cables.

It uses the ever so popular PCIe interface standard and is fully OHCI compliant. The products accommodate off-the-shelf IEEE-1394 OHCI drivers from WindowsTM & Linux-based operating systems. No driver modification/installation is required.

CANbus

Vehicle Multiprotocol Interface Device

CANBus PCIe interface

The Vehicle Multiprotocol Interface Device excels in applications requiring real-time, high-speed manipulation of hundreds of CAN frames and signals, such as hardware-in-the-loop (HIL) simulation, rapid control prototyping, bus monitoring, automation control, and more. The NI-XNET device-driven DMA engine enables the onboard processor to move CAN frames and signals between the interface and the user program without CPU interrupts, minimizing message latency and freeing host processor time for processing complex models and applications.

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