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5.3 MISCELLANEOUS SETUP PARAMETERS
The following section describes miscellaneous the setup parameters.
5.3.1 TEMPERATURE DISPLAY UNITS
Purpose: This allows selection of the type of temperature units to display on the Operator
Console. All temperature related values will be displayed in the selected units.
IMPORTANT: This setting will not affect the temperature units displayed at a 780/GCC-9000
Group Communications Controller. The GCC may be set independently.
Setting: DEGREES F or DEGREES C
Procedure: Adjust the setting to the desired temperature units (°F or °C).
IMPORTANT: To minimize possible confusion, it is recommended that the temperature units
be set the same on the HTC and any other communicating devices.
5.3.2 VERSION OF FIRMWARE AND HARDWARE
Purpose: The first three digits indicate the revision level of the firmware programmed into the
controller. As new features are added to the HTC, the firmware revision level is incremented to
allow the user to determine which features are available for the particular unit being used.
5.3.3 EXTERNAL INPUT PORT
Purpose: This input port may be used as an OVERRIDE SOURCE to sense a remote dry contact
closure. This will override the controller's temperature control and force its output switch off or on.
Setting: NOT USED, INHIBIT, or FORCE ON
Procedure: If the EXTERNAL INPUT is not being used, select NOT USED. If a remote dry
contact closure should force the output switch off then select INHIBIT. If a remote dry contact
closure should force the output switch on, then select FORCE ON.
If the EXTERNAL INPUT is set to INHIBIT or FORCE ON, then OVERRIDE SOURCE must be set to
EXT. INPUT.
IMPORTANT:
• When used with the INHIBIT/FORCE ON feature, a contact closure sensed by the EXTERNAL
INPUT will initiate the INHIBIT/FORCE ON mode. An open input will cause the controller to
revert to normal temperature control operation.
One possible use of the INHIBIT feature is to use an external device (such as a flow meter)
to provide a contact closure if there is flow in a line. As long as the line has adequate flow,
the heating will be off (INHIBITed from operating). See Appendix C for typical connection
diagrams when using this input.
• EXTERNAL INPUT must be set to INHIBIT or FORCE ON before OVERRIDE SOURCE can be
set to EXT. INPUT. Setting EXTERNAL INPUT to NOT USED or TEMPBUS™ will automatically
set OVERRIDE SOURCE to REMOTE.
5.3.4 FLASH ALARM OUTPUT SETTING
Purpose: Programs both the alarm output relays (dry contact and AC alarm) for flashing or
steady output in case of an alarm condition.
Setting: YES (Flash) or NO (Steady)
Procedure: Set the alarm output relays to flash or not to flash on an alarm condition, whichever
suits the application.
IMPORTANT:
• If the alarm output is used to drive a pilot light, it is recommended that YES be selected
to enable flashing operation. When the output is also configured for normally closed
operation, the pilot light will be on steady for normal operation, flash in case of alarm, and be
extinguished due to a bulb failure or loss of power.
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