Hamilton Sundstrand Company Gas Fuel Metering Valve HFG2.0 - Manual (Page 66)

60 HFG2.0 USER GUIDE
Watchdog expired
The MCE watchdog timer continuously monitors the firmware program.
Should the MCE firmware program stop functioning, or attempt to access
an illegal address, the MCE signals a fault.
This fault does not clear without RESET command.
Resolver to Digital Converter (RDC) failure
The MCE contains a resolver to digital converter chip (RDC) that provides
position feedback information to the DSP. The RDC chip has on-board
health monitoring.
If the RDC detect an internal tracking error, a signal is sent to the MCE.
Upon receipt, the MCE signals a fault.
This fault does not clear without RESET command.
Unregulated Voltage Low
The MCE signals a fault if the reference voltage drops below minimum for
ten (10) seconds
.
If the voltage returns to acceptable level, the fault signal is cleared.
+/- 14V High/Low
The MCE signals a FAULT if the internal ±14 VDC power supplies
exceed operating limits. This fault does not clear without RESET
command.
Input voltage High/Low
The MCE signals a fault if the 120 VDC supply exceeds 180 VDC or
drops below 75 VDC for more than 7.5 seconds
(1 second for
). This fault clears when the 120 VDC supply voltage returns.