Thermon TraceNet TCM 18 - Manual (Page 28)

CONFIG 1 The first parameter line on the display screen indicates
the TCM18 control instructions (ALL ON, ALL OFF,
or BY CKT) for high ground/earth leakage current
trip. The second and third lines indicate the control
instructions for heater operating current and high
temperature trip. An “ALL ON” designation indicates
that the heater circuit will trip on a high value and will
require the operator to press the ACK key and the
condition to clear before the circuit will reset. An “ALL
OFF” setting will leave the circuit in an automatic reset
mode which allows the alarm to disappear when the
condition clears.
Note that the “ALL ON” or “ALL OFF” settings are al-
ways global settings for all eighteen circuits on this con-
troller. A “BY CKT” designation means that an individ-
ual circuit’s trip functions may be set during the circuit
programming process and thus are not global settings.
CONFIG 2 The first parameter line on this display screen indicates
the TCM18 alarm relay configuration options currently
selected (options include “ALARM RLY ALL ALARMS”
which causes the alarm relay to activate on any alarm
or “ALARM RLY TEMP ONLY”) which activates on
temperature alarm events only.
The second parameter line on this display screen in-
dicates whether the relays are configured as “ALARM
RLY NRM CLOSED” or “ALARM RLY NRM OPEN”. A
normally closed relay is of the Form B type and will
open on an alarm event.
Relays of this convention
are quite often used when the alarm/trip contacts are
connected to a DCS system or other type of smart
monitoring device. An advantage of this alarm relay
type is that it also naturally creates an alarm if the
controller/system unexpectedly loses power.
A normally open relay is of the Form A type and will
close on an alarm event. This relay convention is often
used when there is light or some warning device like a
horn connected to the alarm relay contacts.
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