CMU-212 Cabinet Monitor Unit
Operations Manual
Eberle Design Inc.
Page 7
interval is not satisfied, the CMU-212 will cause a LFSA. The CMU-212 will report a
Skipped Yellow Clearance when the Yellow Change interval is less than 100 milliseconds.
The CMU-212 will report a Short Yellow Clearance when the Yellow Change interval is less
than 2.7 +/- 0.1 seconds and greater than 100 milliseconds.
Minimum Yellow Change interval monitoring will be disabled when the MC COIL STATUS
input is not active. There is programming in the Datakey to disable Minimum Yellow
Change interval monitoring on a per channel basis.
2.8 YELLOW PLUS RED CLEARANCE MONITOR
The CMU-212 will verify that the Yellow Change plus Red Clearance interval between the
end of an active Green/Walk signal and the beginning of the next conflicting Green/Walk
signal is at least 2.7 +/-0.1 seconds. When the minimum Yellow Change plus Red
Clearance interval is not satisfied, the CMU-212 will cause a LFSA.
Minimum Yellow Change plus Red Clearance monitoring will be disabled when the MC
COIL STATUS input is not active. There is programming in the Datakey to disable Minimum
Yellow Change plus Red Clearance interval monitoring on a per channel basis.
2.9 LOCAL FLASH STATUS
The CMU-212 will monitor the LF STATUS input. This input is used to indicate to the CMU-
212 that the cabinet should be placed into NFSA as a result of the AUTO/FLASH switch
being transferred to the FLASH postion. When this signal is sensed as not active for
greater than 500 milliseconds the CMU-212 will cause a NFSA. When this signal is sensed
as not active for less than 200 milliseconds the CMU-212 will not cause a NFSA.
2.9.1 LOCAL FLASH STATUS RECOVERY
Recovery from Local Flash Status NFSA will occur when this signal is sensed as active for
greater than 500 milliseconds. When this signal is sensed as active for less than 200
milliseconds the CMU-212 will not cause recovery from Local Flash Status NFSA.
2.10 CIRCUIT BREAKER TRIP STATUS
The CMU-212 will monitor the CB TRIP STATUS input. When one or more circuit breakers
have tripped this input will go to the not-active state. When this signal is sensed as not
active for greater than 500 milliseconds the CMU-212 will cause a LFSA. When this signal
is sensed as not active for less than 200 milliseconds the CMU-212 will not cause a LFSA.
2.11 FLASHER UNIT OUTPUT FAILED ALARM
The CMU-212 will monitor the FLASHER 1-1, FLASHER 1-2, FLASHER 2-1, FLASHER 2-
2 voltage states reported by each AMU-214. The AMU-214 reports the flasher state at the
output assembly. Thus a failed state may indicate a malfunction of the connector system or
flash voltage bus or flasher unit.
When a transition from the inactive state to the active state or a transition from the active
state to the inactive state is absent for greater than 2500 milliseconds, the CMU-212 will set
a status bit in the Type 189 frame. This alarm condition will not cause a FSA. It should
cause the appropriate response in the ATC. This status is non-latching such that once a
status bit has been set, the sensing of five valid transitions of the input will clear the status
bit.
2.12 CMU POWER FAILURE
The CMU-212 will monitor the AC+ RAW 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 AC+ RAW in the ATC. A CMU Power Failure
