TROUBLESHOOTING
© 2014 Mold-Masters (2007) Limited. All Rights Reserved.
Revised 1 Oct, 2014
8-3
Fault and warning messages - contd.
Error
Message
Cause Action
N/Z All the control cards are interrogated in se-
quence, on a working controller you can see the
SCAN LEDs ashing in a sequence as each card
is briey checked for satisfactory communication.
If any card fails to respond to the console then an
N/Z error message is displayed for the offending
zone.
If every zone shows N/Z and no
cards show or ash their SCAN
LEDs then check the communication
lead between the console and the
controller cabinet.
If only one or two zones are dis-
playing N/Z then check the card for
faults. If you have recently changed
any cards and put any older dis-
crete-component cards into a new
controller that has surface-mount
cards then it is possible that the con-
sole’s modern scan speed is too fast
for the older control cards. In such
a condition, check the console baud
rate and try setting it to Low.
If this cures the problem and you
later replace the older card for a
newer surface mount version then
remember to reset the Baud rate
back to high for optimum working.
NONE The console has detected a control card that has
no settings.
This Error message may be seen
eetingly during switch on, it should
disappear after the initial card scan.
If the message persists then you
may need to re-apply the correct
card settings on the Setup page.
REV The card has detected an abnormal input at the
T/C termination that indicates a shorted or Re-
versed thermocouple.
If the REV alarm persists then you
should switch off the controller and
investigate the offending zone.
Alternatively you could slave the
offending zone to a good zone until
you have time to clear the fault.
RTD The RTD monitor cannot see an input (RTD is
open circuit)
Check the RTD and its wiring for a
broken connection.
T/C An open circuit thermocouple has been detected
and no auto-response has been selected in the
T/C Open Error column of the Setup page.
For immediate recovery you can
either slave that control zone to an
adjacent zone or change to open
loop control.
TRC If a triac fails it goes short circuit and passes full
load current.
In such a condition you have lost control of the
load and cannot switch it off from the console.
The TRC alarm ags up the fault state which
relies on operator intervention to manually shut
the system down.
Note: the triac monitor does not function in auto
mode. If the triac were to fail while the zone is run
in auto then the only indication will be an abnor-
mally high zone temperature because the triac
is passing high, uncontrolled current. The TRC
alarm is only seen if a triac fails on a zone that is
running in closed-loop manual condition.
If the triac has failed, return to your
supplier for repair.
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