Model MMU-1600G Series Op Man - Ver 1.07.23 - Rev 20151026DL
Page 16 of 58
2.5.5 Short Yellow Monitoring
Configuration:
Minimum Yellow Change Disable (MYCD) jumpers on the program card disable short Yellow monitoring
for a channel. Typically pedestrian only channels will have MYCD jumpers installed. The testing defaults for this feature
are determined by the jumpers installed on the program card. Typically no jumpers are installed during automated testing.
Test Preformed:
When a channel has a Green or Walk that turns off, a Yellow must follow it and it must stay on for at least
2.7 seconds. When each Green or Walk turns off a 2.7 second timer is started. A Yellow must start within 1 second of the
Green or Walk turning off. If the Red turns on before the Yellow, a short Yellow fault will be generated to show that the
Yellow was skipped. When a Yellow turns on for at least 100 milliseconds another 2.7 second timer is started and must
reach zero before the yellow turns off or a short Yellow fault will be generated. The normal voltage thresholds for this test
are: Reds – ON when above 70V
RMS
and OFF when below 50V
RMS
, Greens, Walks, and Yellows – ON when above 25V
RMS
and OFF when below 15V
RMS
.
Fault Action:
The monitor transfers the Output relay contacts to the fault condition (continuity between the Normally Open
and Common contacts), illuminates the
SHORT YEL
indicator on the front panel, and sets the Minimum Clearance Failure
bit (bit 74) of the Type 129 Frame to 1. The Signal Sequence log and the Prior Faults log will record this fault.
Resetting the Fault:
The monitor remains in this fault condition until the unit is reset by the activation of the front panel
reset pushbutton or the activation of the reset input. Power loss or power interruption will not reset this fault. The Reset log
will record the resetting of this fault.
Modifying Inputs:
Red Enable
: All short Yellow testing will be disabled when this input is below 70V
RMS
.
Load Switch Flash bit (bit 112) of the Type 0 Frame
: All short Yellow testing will be disabled when this bit is set to one.
Feature Interactions:
LED Thresholds
: When LED Thresholds is enabled the monitor senses Greens, Yellows, Reds, and Walks as ON when
their voltage is above 70V
RMS
and OFF when below 50V
RMS
for the short Yellow test.
Flashing Yellow Arrow Left Turns
: When Flashing Yellow Arrow (FYA) Left Turns are enabled and a channel has an
FYA setting with a setting of “G” or “Y” for one of its child channels, then the Yellow of the channel will be used for
terminating the Yellow or Green of the child channel and will be checked for short yellow and skipped yellow. Also,
when Flashing Yellow Arrow (FYA) is enabled and Per Channel Red Enables is enabled and the channel Red Enable is
disabled and Dual Indication / Field Check for the channel is disabled and Minimum Yellow Change Disable for the
channel is not jumpered on the Program Card and the channel has the actual flashing yellow arrow display the monitor
will not include the unused Green or Yellow of that channel in the short yellow tests.
2.5.6 Short Clearance Monitoring
Configuration:
All channels will be monitored for a short clearance fault.
Test Preformed:
When a channel has a Green or Walk that turns off, a conflict channel cannot display a Green, Walk, or
Yellow for at least 2.7 seconds. When each Green or Walk turns off a 2.7 second timer is started. If a conflicting Green,
Walk, or Yellow turns on for at least 100 milliseconds the 2.7 second timer must have reached zero or a fault will be
generated. The normal voltage thresholds for this test are: Reds – ON when above 70V
RMS
and OFF when below 50V
RMS
,
Greens, Walks, and Yellows – ON when above 25V
RMS
and OFF when below 15V
RMS
.
Fault Action:
The monitor transfers the Output relay contacts to the fault condition (continuity between the Normally Open
and Common contacts), illuminates the
SHORT CLR
indicator on the front panel, and sets the Minimum Clearance Failure
bit (bit 74) and Spare Bit #5 (bit 71) of the Type 129 Frame to 1. The Signal Sequence log and the Prior Faults log will
record this fault.
Resetting the Fault:
The monitor remains in this fault condition until the unit is reset by the activation of the front panel
reset pushbutton or the activation of the reset input. Power loss or power interruption will not reset this fault. The Reset log
will record the resetting of this fault.
Modifying Inputs:
Red Enable
: All short clearance testing will be disabled when this input is below 70V
RMS
.
Load Switch Flash bit (bit 112) of the Type 0 Frame
: All short clearance testing will be disabled when this bit is set to
one.
Feature Interactions:
LED Thresholds
: When LED Thresholds is enabled the monitor senses Greens, Yellows, Reds, and Walks as ON when
their voltage is above 70V
RMS
and OFF when below 50V
RMS
for the short Yellow test.
