Alarm Outputs - GE Optica Operator's Manual

January 2006
Additional Voltage Outputs

Alarm Outputs

2-10
It is possible to use either of the analog current outputs as an
additional voltage output by connecting a precision resistor from the
current output to its return. A voltage will be produced equal to the
output current times the load resistance. To produce a voltage output
range of 1 to 5 volts, connect a 250 ohm resistor (0.1% tolerance
recommended).
Using a 250 ohm resistor, the voltage output is calculated by::
(
Tactual Tlower
--------------------------------------------- -
Vout =
(
Tupper Tlower
yielding an output voltage of 1.92V for this example.
(
23 0
-------------------- -
(
100 0
Each alarm output connects to the contacts of a 5-Amp, Form C
(SPDT) relay.
Make connections as follows:
•
For normally open contacts, connect to NO and COM.
•
For normally closed contacts, connect to NC and COM.
Any available parameter can be used to control an alarm relay by
programming the parameter name and its threshold values. An alarm
can also be programmed to monitor the state of the Control, PACER
Balance, or Service indicators. (See Chapter 4, 5 or 6 for
programming instructions).
Two threshold values are programmed for each parameter—an upper
and a lower value. These values designate an alarm band. How they
are used depends on the alarm type programmed. Details of the alarm
bands are shown below.
)
–
× (
5 1
–
)
–
)
–
×
1 1.92V
4 + =
)
–
)
1
+
Installation