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Automatic Self-Diagnostics

    Last Modified: May 15, 2018

    C Series Functional Safety modules run a range of automatic self-diagnostics that continuously check for module hardware and power supply faults. Automatic self-diagnostic faults send the module into Fail-safe Mode. The Check Module Status method in LabVIEW will return an Internal Error or Temperature Fault, depending on the fault.

    Some of the automatic self-diagnostics implemented by all C Series Functional Safety modules include:

    • DI reference compares
    • Redundant DO FETs
    • Watchdog timers custom-designed for high accuracy
    • Internal temperature monitoring
    • Power supply voltage monitoring on external supply and all internal rails
    • Redundant ADC, signal conditioning and muxes on AI channels
    • Range checks on AI channels
    • High accuracy AI reference compares

    Errors detected by automatic self-diagnostics on analog configurations will assign a low low current region to all affected channels and generate a flashing pattern on the Internal Fault LED.


    Every DO channel implements redundant FETs and meets SIL3 capability. To create additional redundancy on DO channels, only connect loads above 20 mA. If both FETs fail in the closed position, the open circuit diagnostic will return a fault.

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