National Instruments OP-8940 32-Channel Pass-Through Fault Insertion Module

The National Instruments OP-8940 (Part Number: 787858-01) Pass-Through Fault Insertion Module is a 32-channel passthrough board designed for use with the NI SLSC-12001 platform during hardware-in-the-loop (HIL) testing. In order to replicate open or broken connections in switch, load, and signal conditioning (SLSC) modules, this module offers feed-through channels. The OP-8940 is also useful in a variety of testing settings because it allows fault injection via shorts between pins, shorts to battery voltages, and shorts to ground.

Across its 32 channels, the OP-8940 module has 112 independently programmable relays. Seven relays for fault injection are included in each pair of two signals, enabling extensive testing capabilities. With the proper terminal blocks, cables, and rear transition interfaces (RTIs), users can integrate the OP-8940 with PXI or CompactRIO modules and connect input signals to the RTI's fault buses. The module can be used in a variety of testing scenarios because of its flexibility.

Two sets of eight differential channels (or sixteen single-ended channels) make up the board architecture. Each group has a set of relays for fault insertion. With the Front Interface connectors on the left and the SLSC backplane connectors on the right, the board's configuration guarantees a streamlined design that makes integration with current systems simple. There are seven relays in each differential pair of signals in the Fault Insertion Unit (FIU) part of the OP-8940, for a total of 112 relays. Relays can be individually controlled, providing accurate fault simulation capabilities.

The FIU's use of relay technology enables great density and quick reaction times (<0.5 ms). But even for short periods of time, this technology is susceptible to peak current. Consumers are in charge of restricting the maximum current by adding resistors to the signal or VBus, depending on the cabling and capacitor in the circuit. Peak currents can approach 5A before the internal current limit trips, even though the VBus has a 0.1A power supply constraint. This could permanently harm the relay. An RMA may be issued for repair in the event that a relay fails in short mode. Furthermore, in order to repair a malfunctioning relay, OPAL-RT permits personnel who possess a valid IPC-610 certification and expertise doing through-hole lead-free and no-clean soldering.