CMUip-2212 Cabinet Monitor Unit
Operations Manual
Eberle Design Inc.
Page 8
2.12 CMU POWER FAILURE
The CMUip-2212 will monitor the MAINS input and the NRESET and POWERDOWN
cabinet control inputs to determine a CMU Power Failure response. The POWERDOWN
signal in the False (low) state indicates loss of Mains voltage in the ATC. A CMU Power
Failure will be recognized when both the POWERDOWN and NRESET signals are False
(low) for greater than 100 ms or the MAINS voltage is below the dropout level.
The 24VDC Monitor function (section 2.1) will be disabled while the POWERDOWN signal
is in the False state. The 24VDC FAIL indicator will flash at a 2Hz rate (section 4.1.2).
2.12.1 MAINS VOLTAGE LEVEL SENSE
The CMUip-2212 will monitor the MAINS input and the LV+ or HV+ SIGNAL inputs reported
by each HDSP. When the CMUip-2212 MAINS voltage is less than the Dropout voltage
(section 5.1) for greater than Mains Level Sense timing (section 5.2) the CMUip-2212 will
cause a NFSA. Once NFSA has been set, the POWERDOWN and NRESET signals will
not be monitored until all Mains voltages have exceeded the Mains Restore voltage
(section 5.1).
2.12.2 POWER INTERRUPT
The CMUip-2212 will disable monitoring of the +12VDC and +24VDC power supply inputs
when either the POWERDOWN or NRESET input is False (low). When the POWERDOWN
and NRESET signals are both False (low) the CMUip-2212 will cause a NFSA.
2.12.3 POWER RECOVERY
When the POWERDOWN input is True (high) and the NRESET signal goes from False
(low) to True (high) the CMUip-2212 will begin timing the programmed Minimum Flash
Interval. During the Minimum Flash Interval the CMUip-2212 will be in NFSA.
2.12.4 POWER UP
Following initial application of MAINS voltage the CMUip-2212 will maintain a NFSA until
the POWERDOWN input is True (high) and the NRESET signal goes from False (low) to
True (high). The CMUip-2212 will then begin timing the programmed Minimum Flash
Interval. During the Minimum Flash Interval the CMU will be in NFSA.
2.12.5 MINIMUM FLASH INTERVAL
During the Minimum Flash Interval the CMUip-2212 will be in NFSA. The Minimum Flash
Interval will be programmed in the Datakey between the limits of 6 seconds to 16 seconds
with an incremental adjustment of 1 second. The CMUip-2212 will not set a FSA during the
Minimum Flash Interval.
2.13 FIELD OUTPUT CHECK
The Field Output Check is a continuous verification that the field signal output states set by
the ATC are properly driven to the signal loads and correctly sensed by the HDSP and
CMU-2212. It is an enhanced function made possible by the Serial Bus #1 communications
between the ATC and CMU-2212. The CMUip-2212 will receive a Type 81 (67) message
from the ATC that contains an image of the controller output commands to the load
switches. When a fault condition triggers the CMU-2212, the Type 81 (67) message
information received while the fault condition was being timed will be used by the CMUip-
2212 to determine whether the sensed field signal input status corresponded to the ATC
output commands. This diagnostic information may then be used to isolate whether the
fault condition was caused by an ATC malfunction or a failure in the load switch and/or field
wiring.
