Keysight M8131A 16/32 GSa/s Digitizer User’s Guide 21Introduction 1LEDsThe M8131A front panel include the following LEDs:• Status LEDsThe “Fail” and “Access” LEDs are available at the front panel to indicatethe status of the M8131A module:• The green ‘Access’ LED indicates that the controlling PC exchangesdata with the M8131A module.• The red ‘Fail’ LED has following functionality:• It is ‘ON’ for about 30 seconds after powering the AXIe chassis.• After about 30 seconds the LED is switched ‘OFF’. If an externalPC is used to control the AXIe chassis, this PC can be poweredafter this LED has switched OFF.• During normal operation of the module this LED is ‘OFF’. Incase of an error condition such as e.g. a self-test error, the LEDis switch ‘ON’.• In case the output relay has shut-off because of an externaloverload condition, this LED flashes.• Trig In LED - This LED indicates that an externally applied signalmatches the adjusted threshold to be used as a Trigger. The LED turnson for ~100 ms for each detected edge of the correct polarity. I.e. arising edge turns the LED on for 100 ms if the polarity is adjusted torising. If the polarity is adjusted to rising and a falling edge is externallyapplied, the LED remains OFF. The functionality of this LED is for futureuse and is currently not supported.• Sample Clk In LED - This LED is green whenever the clock is providedto M8131A when an external Sample Clock Source is used.The functionality of this LED is for future use and is currently notsupported.• Ref Clk In LED - This LED is green when a valid signal at Ref CLK IN isdetected. In case of invalid signals, it is RED. The functionality of thisLED is for future use and is currently not supported.
