TRACE
MATE-277V Chapter 4
Operation
4.1
Alarms
When an alarm condition occurs, the form c dry alarm
contact reacts and the corresponding alarm LED comes
on to indicate the cause of the alarm. Fault diagnosis for
these alarms is listed below.
RTD Fail: If the RTD sensor is not connected or shorted,
RTD FAILalarm LED will turn on. Check that the RTD
sensor is properlyconnected. This alarm is not latched
and will be reset as soon as the RTD is properly
connected. In the event ofan RTD failure, the heater
output is turned offto prevent a runawayheating
situation.
LowTemperature: Once the actual temperature is below
thelowtemperaturealarm setpoint, LOTEMPalarm
LEDwill turn on. Thiswill normally indicate that the
heater circuit is not providing enough heat to maintain the
setpoint. When a system is first turned on this alarm may
be activated. It is particularlyuseful in taking corrective
action in freezeprotection systems to prevent a burst
pipe.This alarm is not latched and will bereset as soon as
thealarm condition disappears.
High Temperature: Once the actual temperature is above
the high temperature alarm setpoint, HI TEMPalarm
LED will turn on. This alarm is not latched and will be
reset as soon as the alarm condition disappears.
Current Fail:This alarm is activated when theTraceMate-
277V control calls for heat and a heater current less than
thecurrent fail alarm setpoint flows. Either the continuity
of the wiring and heat tracing cable is defective or a very
small heater is being switched. In order to detect faults on
dormant systems with the TraceCheck feature, which
turns on the heaters for several seconds every 24 hours,
this alarm is latched. Thus, once the condition is detected,
thealarmwill remain on until theTraceMate-277Vis
reset.
GroundFaultTrip:This alarm is activated when the
groundfault currentis abovethe groundfault tripalarm
setpoint.A ground fault is a current to ground caused by
moisture, corrosion or insulation breakdown. Often the
amount ofground fault current is not enough totrip the
heater circuit breaker but could result in a serious fire
hazard, especiallywith self-regulating cable.
When a ground fault is detected, the heater will be
switched off, even if the control is calling for heat.This
eliminates the needfor an expensive groundfault circuit
breaker. Largeground fault currentswilltrip theheater
circuit breaker, so an intentional time delayis allowed for
thebreaker to clear high fault currents,which canoccur
on solidly grounded systems.
Since the heater maybe shut offafter a ground fault, it is
very important that the alarm outputs be used so
corrective action can be taken quicklyenough to prevent
a process shutdown due to the loss of heat to a pipe.
Ground fault detection only works with resistance or
solidlygrounded systems. Ifthe system is ungrounded, it
must be grounded or an artificial ground must be created
by means ofa zip-zag transformer. Once a ground fault
condition is detected, it remains latched until it is reset.
Status Indicators
Power On Indicator: When incoming voltage is applied
to the TraceMate-277V, the green PWR ON indicator
LED should be on. If this LED is not on, check that the
appropriate voltage is present byconnecting a meter
across terminals 1 and 2. If voltage is present and the
LED is off, the controller should be replaced and sent to
the factory for service.
Heater On Indicator: Whenever the heater is on, the green
HTR ON indicator LED will be on. This is useful for
checking correct operation of the control. Ifthe ground
fault alarm light orRTD fail alarm light ison, the heater
will not switch on even if the actual temperature is below
thesetpoint.
Alarm Reset
The low/high temperature and RTD fail alarms reset as
soon as the condition disappears. The ground fault trip
and current fail alarm are latchedalarms. Alatched alarm
will remain even if the alarm condition disappears. To
reset the latched alarms, remove incoming power for a
few seconds byopening and reclosing the circuit breaker.
Provided the alarm conditions are no longer present, the
alarms should all be reset when power is re-applied to the
TraceMate-277V. It is also possible to reset the latched
alarms bymomentarily switching S11 towards its ON
position ( refer to Figure 2.1 ) even ifthe TraceMate-
277V is at control with power applied.
HeaterSetpoint andAlarm Setpoints
As stated in chapter 2, five setpoints can be adjusted by
properly setting up S1-9 and JP1 ( refer to Figure 2.1 ).
S1-9 consisits of9 switches. They are S1, S2, S3, S4, S5,
S6, S7, S8 and S9. These 9 switches generate a Setpoint
Number in a range of 0-511. The exact value of this
Setpoint Number equals the sum ofthe contributions by
each switch. Ifa switch is in ON position, its contribution
tothe Setpoint Number equals its labelled value on the
board. Otherwise, its contribution is zero. For example, if
all 9 switches are in ON position, Setpoint Number =
1+2+4+8+16+32+64+128+256 = 511. If only switches
S3 and S5 are in ON position, Setpoint Number =
0+0+4+0+16+0+0+0+0 = 20.
Depending on the jumper position ofJP1, the Setpoint
Number generated by S1-9 can beinterpreted as either
heater setpoint, or lowtemperaturealarm setpoint, or high
temperaturealarm setpoint,orgroundfault tripalarm
setpoint, or current fail alarm setpoint.
