889-3809-02
Model 2018E Operations Manual Rev Apr 2020 Page
4
of 39
2.1.5
RED ENABLE
The presence of the proper voltage at this terminal (Red Interface Connector - Pin 20) enables the monitor to detect
the absence of voltage on all field signal inputs of a channel.
The Red Enable input is sensed as ON when the input voltage exceeds 70V
RMS
and is sensed as OFF when it is less
than 50V
RMS
.
The Model 2018E will not recognize state changes of the Red Enable input while AC power is not valid. This
ensures that short power interruptions do not cause unintended state changes of the Red Enable input.
When the Red Enable input is sensed as OFF the Multiple Indication and Short Yellow monitoring will be disabled
unless the MI/SY ON (Multi Indication & Short Yellow Monitoring are Always ON) option jumper is installed.
Typical Connection: Control point that has 120VAC when the cabinet is in normal operation.
2.1.6
SPECIAL FUNCTION INPUTS
The monitor provides two Special Function inputs, Special Function 1 (Red Interface Connector – Pin 8) and
Special Function 2 (Red Interface Connector – Pin 6). The presence of an active signal on these inputs disables the
monitor’s ability to detect the absence of voltage on all field signal inputs of a channel (Red Fail monitoring).
The Special Function inputs are sensed as ON when the input voltage exceeds 70V
RMS
and are sensed as OFF when
it is less than 50V
RMS
.
The Model 2018E will not recognize state changes of the Special Function inputs while AC power is not valid.
This ensures that short power interruptions do not cause unintended state changes of the Special Function inputs.
There are two Option Switches (Special Function 1 Invert and Special Function 2 Invert) that allow the user to
invert the ON and OFF states for each of the Special Function inputs. The
Special Func 2 Enable
user option in
RaeComM must be selected in order for Special Function 2 to function.
Typical Connection: Unterminated or Preemption circuitry.
2.1.7
MC COIL INPUT
The monitor provides an input to monitor the state of the Mercury Contactor (MC) Coil (Rear Edge Connector –
Pin EE). When this input is ON, the monitor disables the following functions: Red Fail monitoring, Flashing Don’t
Walk monitoring, Multiple Indication monitoring, and Short Yellow monitoring.
The MC Coil input is sensed as ON when the input voltage exceeds 70V
RMS
and is sensed as OFF when it is less
than 50V
RMS
.
The Model 2018E will not recognize state changes of the MC Coil input while AC power is not valid. This ensures
that short power interruptions do not cause unintended state changes of the MC Coil input.
Typical Connection: MC Coil.
2.1.8
DC GROUND
A voltage reference point and current return for the External Reset input, Watchdog Timer input, +24 V Monitor
input, and +24 VDC input circuits. This termination (Rear Edge Connector - Pin Y) is not connected to either the
AC Neutral or Earth Ground within the unit.
Typical Connection: Power Supply DC Common.
2.1.9
+24 VDC INPUT
A +24-volt DC input (Rear Edge Connector - Pin 23 & Pin AA) is monitored to assure 24 VDC levels.
The actual DC Voltage is measured and monitored at least 1000 times per second to ensure proper value. The 24
VDC Input can be accessed in real-time via the serial port. The actual voltage is also recorded in the Signal
Sequence Log if a fault occurs.
Typical Connection: Power 24VDC.
2.1.10
WATCHDOG TIMER INPUT
The Watchdog Timer input (Rear Edge Connector - Pin 22) is a logic level input. This signal must toggle between
the low state (nominal 0VDC) and the high state (nominal 24VDC). When not pulled low, the input is internally
biased to the high state (+24VDC). Actual Watchdog Timer voltage is measured and monitored at least 1000 times
per second to determine the status of the input. The actual DC voltage level of the Watchdog Timer input can be
accessed in real-time via the serial port. The actual voltage is also recorded in the Signal Sequence Log if a fault
occurs.
Typical Connection: Controller Watchdog Output