
32
GOSSEN METRAWATT GMBH
Heating Current Monitoring
FunctionHeating current is acquired with an external transformer (e.g. GTZ 4121).
An alarm is triggered if the current setpoint is fallen short of by more than 20% with acti-
vated heat (control output I active), or if current is not “off” when the heat is switched
off. The alarm is not triggered until heating current is high enough when output I is
active, or when current drops to zero when output I is inactive.
Monitoring is inactive if the controller is switched to
oFF
, as well as in the case of contin-
uous and step-action controllers.
AMPS
current
setpointHeater phase current is entered for this parameter.
AMPS
can be set to
Auto
for automatic adjustment
with the heater switched on. The measured current value is saved to memory.
Heating Circuit Monitoring
Function–
Can be set to active or inactive with the “alarm” configuration digit
(see Configuration).
– Without external transformer, without additional parameters
– Assumes correct optimization of
tu
and
Pb 1
control parameters,
i.e. heating circuit monitoring must be activated before self-tuning is started.
In the event of manual optimization or subsequent adaptation of control parameters,
the lower limit value for the
tu
parameter must be observed:
Pb 1
MR
minimum
tu
=
•
50%
∆ϑ
⁄
Dt
∆ϑ
⁄
Dt = maximum temperature rise during actuation
– Error message
LE
appears after approximately 2 times
tu
, if heat remains on at
100% and measured temperature rise is too small.
– Monitoring is not active:
where controller sort = limit transducer, actuator or step-action controller
during self-tuning
with standard signal input (designation B2)
where manipulating factor limiting
YH
< 20%