Omron E5GC-600 Manual page 18

E5GC-600
Temperature High/Low Limit Controller
This document is an addendum to the E5  C User's Manual (H174-E1-xx). Please refer to this
document for installation, specifications, wiring, etc. The purpose of this document is to show the
programming steps to set the specified controllers up for FM temperature high limit monitoring.
This set up will assign Alarm 1 Output as the limit output for all dedicated FM approved units. If the unit
is equipped with an event input this can be used to cancel the alarm latched condition. If it is not so
equipped the use of the "PF" key on the front of the unit can also be used for this purpose. Some of the
controllers also have the option for a transfer output which can be used to transfer the process value to
a chart recorder for recording purposes.
Limit Control Function (Limit Output)
When a Temperature Controller is controlling the temperature of a furnace or other heating device, a
malfunction in the Temperature Controller may cause the furnace temperature to rise, resulting in
damage to the heated product or the furnace itself. When this situation occurs with the Limit Controller
and the temperature rises above the preset limit temperature the Alarm limit output will OPEN ("SUB1"
LED indication ON) and the heater system circuit will be shut down to stop the heat source. In addition,
the limit output will remain OPEN even when the temperature returns to the normal range. A safer
system can be constructed because the limit output will remain OPEN until it is reset manually.
With the Limit Controllers, it is possible to establish a lower limit instead of an upper limit so that the limit
function operates when the temperature falls below the limit setting value (Cooling Application). When
an input error occurs, the Limit output will OPEN ("SUB1" LED indication ON) and will remain in this
condition until the sensor error is fixed and a reset is provided.
Using the Limit Controller Function
When the measured temperature (PV) exceeds the limit setting value, the limit output relay OPENS and
the SUB1 operation indicator turns ON. If the limit output relay OPENS (limit alarm is ON), the limit output
relay will remain OPEN until the operator checks operation and performs resetting operation.
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