Custom FlexRIO Adaptor Module supports HIL Test Upgrade

Challenge

Our client has a client (the end-user) for which they developed an HIL test system several years prior. Parts were obsolete and the system needed an upgrade. The prior system had many custom-designed electronic components which could not be replaced without a complete redesign.

Consequently, our client wanted to use COTS. However, one device needed 28 VDC digital I/O, a couple of lines which carried significant current (amp, not milliamp, levels) and at switching rates much higher than a COTS solid state relay could provide.

Solution

Viewpoint reviewed the requirements and created a hybrid COTS-custom solution. We combined an NI FlexRIO module with a custom FlexRIO Adapter Module (FAM) for the front end to satisfy the 28 VDC signals levels and required current drive.

Benefits

• COTS FlexRIO integrates into the remainder of our client’s PXI-based test system.
• The Custom I/O was designed for flexibility. Our client can use this FAM for both their initial end-user and other programs / clients too.
• Reduced cost relative to a completely custom solution.
• Delivery time reduced by months relative to a custom solution

FAM Overview

The custom FAM interfaced with the NI FlexRIO module, which offered low-level digital I/O (3.3 V logic), to digital signal conditioning hardware that provided the 28 VDC signal levels and required current drive.

Each I/O pin was configurable as input or output (source or sink). Each bank of 4 channels had an adjustable threshold level set via an adjustable DAC output. Some of the channels are designed for amp-level current drive, while the remainder were 250 mA. All I/O was fused appropriately.

Viewpoint also developed LabVIEW FPGA and VHDL to enable our client and the end-user to:

• Configure the I/O as in or out.
• Communicate to the DAC to allow custom input threshold trigger levels.
• Read and write the digital data.