889-3809-00
Model 2018 Operations Manual Rev Apr 2020 Page
5
of 41
2.1.10
WATCHDOG TIMER INPUT
The Watchdog Timer input (Rear Edge Connector - Pin 22) is a logic level input. This signal must toggle
between the low state (nominal 0VDC) and the high state (nominal 24VDC). When not pulled low, the
input is internally biased to the high state (+24VDC). Actual Watchdog Timer voltage is measured and
monitored at least 1000 times per second to determine the status of the input. The actual DC voltage
level of the Watchdog Timer input can be accessed in real-time via the serial port. The actual voltage is
also recorded in the Signal Sequence Log if a fault occurs.
Typical Connection: Controller Watchdog Output.
2.1.11
EXTERNAL RESET INPUT
The External Reset input (Rear Edge Connector - Pin Z) is a logic level input. A voltage of less than 4V
DC
is
recognized as a low and a voltage greater than 12V
DC
is recognized as a high. This signal is low state for the true
state. When not activated, the input is internally biased to the false (high) non-operate state (+24 VDC). Actual
External Reset voltage is measured and monitored at least 1000 times per second to determine the status of the
input. The actual DC voltage level of the External Reset input can be accessed in real-time via the serial port. The
actual voltage is also recorded in the Signal Sequence Log if a fault occurs.
Typical Connection: Unterminated or tied to +24VDC. Should be used only for automated testing.
2.1.12
CABINET INTERLOCK
The monitor has two terminals internally connected to indicate the presence of the unit to the external circuitry.
These terminals are on the Rear Edge Connector - Pin 24 and Pin 25.
Typical Connection: Interlock circuitry that will not allow the cabinet to operate normally with the monitor
removed.
2.2
OUTPUTS
2.2.1
OUTPUT RELAY
The Output relay of the monitor has a set of isolated Form C contacts. These relay contacts are capable of
switching all loads in the range from two milliamps at 18 volts DC to three amperes at 135V
RMS
.
The open circuit of the Output relay is the circuit that is open when the unit is in the No Fault state and all voltages
are sufficient for proper operation of the Controller Assembly. The relay coil is energized in the No Fault state.
When operating in the 2010 mode, prior to the monitor transferring the Output relay contacts from the Fault state to
the No Fault state, a transition state with a duration of 250 milliseconds occurs. During the transition state the
Output relay contacts are the same as the Fault state and the monitor releases the Stop Timing output.
Typical Connection: Used to control the flash transfer relays.
2.2.2
STOP TIMING OUTPUT
The Stop Timing output of the monitor is an Open Collector output. When the output is active, the monitor will
pull the Stop Timing output down to 0.8 volts or less.
When operating in the 2010 mode, prior to the monitor transferring the Output relay contacts from the Fault state to
the No Fault state, a transition state with a duration of 250 milliseconds occurs. During the transition state, the
Output relay contacts are the same as the Fault state and the monitor releases the Stop Timing output.
Typical Connection: Stop Timing input of the controller.
2.3
PROGRAMMING CARD
The monitor is fully programmable and requires programming action to provide configuration information.
Programming is accomplished through the use of diodes and jumpers on an interchangeable Programming Card.
The Programming Card plugs into the monitor through a slot in the front panel. The monitor is constructed with
card guides to ease the insertion of the Programming Card. The Programming Card includes card ejectors to ease
removal of the Programming Card. The edge of the Programming Card is flush with the surface of the front panel
when it is properly seated in the program card slot of the monitor. The
PC AJAR
LED will illuminate if the
Programming Card is not properly seated while power is applied.
The monitor can use either a 16-channel Programming Card or an 18-channel Program Card. Refer to the table in
section 2.6 for Programming Card connector pin assignments. The monitor can be configured to accept both types