SSM-LE Series
Operations Manual
Eberle Design Inc.
Page 8
3.2.1 GY ENABLE OPTION
This monitoring function detects simultaneous inputs of active Green and Yellow field signal
inputs on the same channel. It can be used to monitor channels which have an unused Red
field signal input tied to AC LINE such as a five section signal head resulting in the SSM
switch in the Off position.
GY-Dual Indication Monitoring is enabled by the front panel option switch labeled GY
ENABLE. See Section 5.4.1. When the GY-Dual Indication Monitoring option is enabled, all
channels which have the front panel SSM switches OFF will be individually monitored for
simultaneous active Green and Yellow field signal inputs. All channels which have the front
panel SSM switches ON (i.e. enabled for Dual Indication Monitoring) will function as
described above in Section 3.2.
GY-Dual Indication Monitoring will be disabled when the RED ENABLE input is not active.
3.2.2 WALK DISABLE OPTION
This option will modify the operation of Red Fail and Dual Indication Monitoring. When
enabled, the Red Fail and Dual Indication Monitoring function will not monitor the Walk field
outputs. Absence of signals on the Green, Yellow, and Red field outputs of a channel will
place the SSM-LE Series
into the Red Fail fault mode causing the Output relay contacts to
transfer. Presence of active signals on the Walk outputs will not cause a Dual Indication
when concurrent with active Red or Yellow signals. This function is enabled by the Option
Switch called "WALK DISABLE" on the front panel. See Section 5.4.4.
3.3 MINIMUM YELLOW CLEARANCE MONITORING
The SSM-LE Series
will verify that the Yellow Change interval is at least the Clearance Fail
Fault time (7.4). The Yellow Change interval consists of the duration of time in which the
Yellow field signal input is active in a sequence from Green to Yellow to Red. When this
minimum interval is not satisfied the SSM-LE Series
will enter the fault mode, transfer the
OUTPUT relay contacts to the Fault position, and display the CLEARANCE status screen.
The SSM-LE Series
will remain in the fault mode until the unit is reset by the RESET button
or the EXTERNAL RESET input.
Minimum Yellow Change Monitoring will be disabled when the RED ENABLE input is not
active. A set of switches labeled “SSM” is provided on the SSM-LE series Signal Monitor
front panel to enable Clearance Monitoring on a per channel basis.
3.4 EXTERNAL WATCHDOG MONITORING
This function monitors an optional external watchdog output from a Controller Unit or other
external cabinet circuitry. The external source should toggle the EXTERNAL WATCHDOG
input logic state once every 100 msec. If the SSM-LE Series
does not receive a change in
state on the EXTERNAL WATCHDOG input for the External Watchdog Fault time (7.4), the
SSM-LE Series
will enter the fault mode, transfer the OUTPUT relay contacts to the Fault
position, and display the EXT WATCHDOG status screen. The SSM-LE Series
will remain
in the fault mode until the unit is reset by the RESET button or the EXTERNAL RESET
input. A Power Failure will also reset the External Watchdog fault state of the monitor (see
Section 2.4).
This function is enabled by the front panel Option Switch called WD ENABLE (see Section
5.4.3). The EXTERNAL WATCHDOG input is harnessed to spare pin MSB-S on the front
panel B connector by the factory.
3.5 PROGRAM CARD ABSENT INDICATION
If the Program Card is absent or not seated properly in the edge connector, the SSM-LE
Series
will enter the fault mode, transfer the OUTPUT relay contacts to the Fault position,
