Startup and operation
Page 19
UPT-6011
Version 5
7.2.4
Configuration of the alarm relay
If the switch is set to "Alarm relay de-energized at alarm / PC CONFIGURATION", you can select more alarm
output configurations in the ROPEX visualization software (
section 8.12 "USB interface for visualization soft-
7.3
Heating element
7.3.1
General
The heating element is a key component in the control loop because it is not only a heating element but also a
sensor. The geometry of the heating element is too complex to be discussed at length here. We shall therefore
only refer to a few of the most important physical and electrical properties.
The measuring principle used for this system requires a heating element alloy with a suitable temperature coeffi-
cient TCR, i.e. one whose resistance increases as the temperature rises.
Too low a TCR leads to oscillation or uncontrolled heating.
If a heating element with a higher TCR is used, the controller must be calibrated for it.
The CIRUS
®
Temperature Controller is suitable for temperature coefficients in the range 400…4000 ppm/K.
The base resistance of the heating element increases continuously during operation (owing to the
design). The "AUTOCAL" function must therefore be run again approximately every 100,000 heat-
sealing cycles in order to prevent ACTUAL temperature measuring errors.
7.3.2
Replacing the heating element
The supply voltage (all poles) must be disconnected from the CIRUS
®
Temperature Controller in
order to replace the heating element.
The heating element must be replaced in accordance with the instructions provided by the manu-
facturer.
Each time the heating element is replaced, you must run the "AUTOCAL" function (
zero calibration AUTOCAL (AC)" on page 25) and set the correction factor Co (
section 8.7.9 "Correction factor
Co" on page 54). Any production-related resistance tolerances of the heating element are compensated in this
way.
0
5
1
2
3
4
6
7
8
9
AU
X
CONF
IG
URATI
ON
ALARM
OU
TP
UT
ENER
GIZ
ED
(A
T AL
ARM)
DE-E
NERG
IZ
ED
Alarm relay contact
opened by alarm
Alarm relay contact
closed by alarm.
(factory setting)
!
!
!