2010ECL-NYC SERIES SIGNAL MONITOR
OPERATIONS MANUAL
Eberle Design Inc.
Page 5
A Clearance (short or absent Yellow) fault condition will place the Signal Monitor into the fault
mode causing the Output relay contacts to close and enabling the Stop-Time output to the
controller. This occurs when a Red input signal to a channel is active following the termination
of an active Yellow input signal which is less than the minimum duration, including zero (i.e.
skipped).
2.5 AC LINE BROWN-OUT DETECTION
When the AC Line voltage is below the "drop-out" level the Signal Monitor will suspend all
fault monitoring functions, close the Output relay contacts, and enable the Stop-Time output
to the controller. The AC POWER indicator on the front panel will flash at a rate of 2Hz to
indicate the brown-out status. When the AC Line voltage returns above the "restore" level
the monitor will resume normal operation and the AC POWER indicator on the front panel
will remain illuminated.
The AC Brownout dropout and restore voltage levels are selected by the AC Line Brown-out
Select jumper labeled SEL5. See Section 4.5.5.
AC Line Brown-out Detection is provided to prevent a dark intersection in the event a brown-
out causes the cabinet controller to release control of the intersection. If this occurs and the
intersection is not placed into flash, the monitor will detect a Red Failure (absence of signal)
or WDT Error and will require a manual reset.
The "low AC Line Voltage" level on the
Controller Unit should be set at least 5 volts below the monitor drop-out level.
2.5.1 MINIMUM FLASH TIME
A Minimum Flash time option can be selected (see Section 4.5.2) which provides a flash
interval of at least 6 seconds and at most 10 seconds in duration following a power-up, an
AC Line interruption, or a brownout restore. During this interval the unit will suspend all fault
monitoring functions and close the Output relay contacts. The AC indicator on the front panel
will flash at a rate of 4Hz.
The minimum flash interval will be terminated after at least 6 seconds if the Watchdog input
has made 5 transitions between the True and False state and the AC Line voltage is greater
than the restore level.
2.6
LEDGUARD
®
LED FIELD SIGNAL SENSING
The Signal Monitor can be configured to use a technique called
LEDguard
®
that is designed
to better monitor the characteristics of LED based signal loads (See Section 4.4.6). Each
field signal input is measured and compared to both a high threshold and a low threshold
value to determine On / Off status. This differs from conventional operation where the active
threshold is picked according to the color of the field signal. Once the high and low On / Off
thresholds (Section 8.1.2) have been determined using the input RMS voltage, the individual
fault monitor functions use the appropriate threshold to determine if a fault condition exists.
LEDguard
®
Green/Walk
Yellow
Red/Dont Walk
Conflict
Low
Low
---
Red Fail
High
High
High
Dual Indication
Low
Low
Low
Clearance
Low
Low
High
2.7 RECURRENT PULSE DETECTION
This error detection function supplements the normal Conflict, Dual Indication, and Red Fail
monitoring algorithms for sensing faults that are intermittent or pulsing in nature. The RMS-
Engine is designed to filter out short term transients commonly found on the electrical service
and provide noise immunity against false signal detections. The Recurrent Pulse detection
