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MMU2-1600GE series Operations Manual Rev Apr 2020 Page
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The presence of the proper voltage at this terminal also enables Minimum Yellow Change / Red
Clearance Interval Monitoring and Field Check / Dual Indication Monitoring. The absence of the proper
voltage at this terminal inhibits Minimum Yellow Change / Red Clearance Interval Monitoring.
The monitor 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.
Typical Connection: Control point that has 120VAC when the cabinet is in normal operation.
2.1.6
LOGIC GROUND
A voltage reference point and current return for the Reset input, Controller Voltage Monitor input, +24V Monitor I
input, +24V Monitor II input, Type Select input, +24V Monitor Inhibit input, Local Flash Status input, and Port 1
Disable input as well as the Port 1 SDLC communications signals. This termination (Connector A - Pin T) is not
connected to either the AC Neutral or Earth Ground within the unit.
Typical Connection: Power Supply DC Common and/or Controller Logic Ground.
2.1.7
+24V MONITOR I
+24V Monitor I (Connector A - Pin S) is monitored to assure a 24 volt DC level.
Typical Connection: Power 24VDC or Cont24VDC Output.
2.1.8
+24V MONITOR II
+24V Monitor II (Connector B - Pin R) is monitored to assure a 24 volt DC level. This input can
optionally be used to monitor a +12VDC supply (detector power) if the 24V-2 to 12VDC feature is enabled.
Typical Connection: Power 24VDC, Cont24VDC Output, or Power 12VDC.
2.1.9
24V MONITOR INHIBIT
+24V Monitor Inhibit input (Connector A - Pin n) is a logic level input used to disable monitoring of the +24V
Monitor I and +24V Monitor II inputs. Application of a True (Low) state to this input inhibits the operation of the
+24 Volt Monitor and sets the +24 Volt Monitor Inhibit bit (bit 60) of the Type 129 Frame to 1.
Typical Connection: Unterminated or tied to +24VDC.
2.1.10
CONTROLLER VOLTAGE MONITOR (CVM)
The Controller Voltage Monitor input (Connector A - Pin V) is a logic level input. This input must stay in a low
state (nominal 0 volts) for normal signal operation. When high or floating, the monitor will be in the fault
condition. This input is sometimes used by controllers to perform time of day flash operations. In this case, the
24V Latch jumper on the program card cannot be installed for proper operation.
Typical Connection: Controller CVM Output
2.1.11
TYPE SELECT
The monitor operates as a Type 16 monitor with sixteen channels when the Type Select input (Connector A - Pin
HH) is at logic True (Low) state; otherwise it operates as a Type 12 monitor with twelve channels.
Type 16: When configured for Type 16 operation, each channel has the capability of monitoring a Green (Walk), a
Yellow, and a Red (Don’t Walk) field signal output at the Terminals and Facilities field terminals. Type 16
operation is intended for those applications in which there are three circuits per channel and the monitor channels
have been wired in a one-to-one correspondence with the load switches, as defined in Section 5.5.3, Paragraph 9 of
the NEMA Traffic Controller Assemblies Standards Publication TS 2-2003.
Type 12: When configured for Type 12 operation, each channel has the capability of monitoring a Green, a Walk,
a Yellow, and a Red field signal output at the Terminals and Facilities field terminals. Type 12 operation is
intended for those applications in which downward compatibility with 12 channel Conflict Monitor Units (CMU)
conforming to NEMA Traffic Control Systems Publication TS 1-1989 is required. All Port 1 communications
errors are ignored when the monitor is configured to operate as a Type 12 monitor.
Typical Connection: Logic Ground for Type 16 operation. Unterminated or tied to +24VDC for Type 12 operation.
2.1.12
LOCAL FLASH STATUS
The Local Flash Status input (Connector B - Pin c) is a logic level input. When this input is in the low state
(nominal 0 volts), the monitor will transfer the Output Relay contacts to the fault state and set the Local Flash
Status bit (bit 79) in the Type 129 Frame to 1. At all other times, the Local Flash Status bit of the Type 129 Frame
is set to 0.
Typical Connection: Police Panel flash switch and/or inside cabinet flash switch
