CMU-24VDC-ITL Cabinet Monitor Unit
Operations Manual
Eberle Design Inc.
Page 12
A channel will be sensed active when the load current exceeds 105% of the Channel
Current Sense Threshold programmed for that channel in the Datakey. A channel will not
be sensed active when the load current is less than 95% of the Channel Current Sense
Threshold programmed for that channel in the Datakey. A load current value between 95%
and 105% of the Channel Current Sense Threshold may or may not be sensed active. This
provides a hysterisis value of +/- 5% of the Channel Current Sense Threshold.
The Channel Current Sense Threshold should be programmed for each monitored channel
based on the minimum signal load under all worst case conditions.
3.4 PDA CONTROL SIGNAL INPUTS
3.4.1 LOCAL FLASH STATUS
The cabinet should be wired such that operation of the cabinet in AUTO mode will place
24VDC on the LF STATUS pin. Operation of the cabinet in FLASH mode should be open
circuit on this input. This input will be considered active when the input voltage exceeds the
Active threshold defined in Cabinet Control 5.1. This input will not be considered active
when the input voltage is less than the Not Active threshold defined in Cabinet Control 5.1.
The CMU-24VDC will report the state of this input in the Type 189 frame. See section 2.9.
3.4.2 MAIN CONTACTOR (MC) COIL STATUS
The cabinet should be wired such that the MC COIL STATUS input is connected to the
24VDC side of the main contactor signal bus relay coil. An active signal on this input
indicates the Signal Bus should be powering the load switches. This input will be
considered active when the input voltage exceeds the Active threshold defined in Cabinet
Control 5.1. This input will not be considered active when the input voltage is less than the
Not Active threshold defined in Cabinet Control 5.1. The CMU-24VDC will report the state
of this input in the Type 189 frame.
3.4.3 MAIN CONTACTOR (MC) SECONDARY STATUS
The cabinet should be wired such that the MC SECONDARY STATUS input will be
connected to the output side of the main contactor signal bus relay. An active signal on this
input indicates the Signal Bus is powering the load switches. This input will be considered
active when the input voltage exceeds the Active threshold defined in Cabinet Control 5.1.
This input will not be considered active when the input voltage is less than the Not Active
threshold defined in Cabinet Control 5.1. The CMU-24VDC will report the state of this input
in the Type 189 frame.
3.4.4 FTR COIL DRIVE STATUS
The cabinet should be wired such that the FTR COIL DRIVE STATUS input is connected to
the FTR COIL DRIVE signal in the DC SIGNAL POWER BUS. An active signal on this input
indicates the flash transfer relays are energized and the field signals are driven from the
load switch outputs. This input will be considered active when the input voltage exceeds the
Active threshold defined in Cabinet Control 5.1. This input will not be considered active
when the input voltage is less than the Not Active threshold defined in Cabinet Control 5.1.
The CMU-24VDC will report the state of this input in the Type 189 frame.
3.4.5 CIRCUIT BREAKER (CB) TRIP STATUS
The cabinet should be wired such that the CB TRIP STATUS input will be connected to the
Auxiliary Switch output of the circuit breaker unit. The active state of this input indicates that
the circuit breaker unit is not in the tripped state. This input will be considered active when
the input voltage exceeds the Active threshold defined in Cabinet Control 5.1. This input will
not be considered active when the input voltage is less than the Not Active threshold
defined in Cabinet Control 5.1. The CMU-24VDC will report the state of this input in the
Type 189 frame.
