210E / 210ECL / 2010 / 2010ECL / 2018ECL 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.
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
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