Commissioning and operation
Page 22
RES-5008
Version 2
8.2.3
Configuration of the alarm relay
8.3
Burning in and changing the heating element
8.3.1
Burning in the heating element
The heating element is an important component in the control circuit, as it is both a heating element and sensor.
Before using a heating element for the first time, please note the following.
Description of the burn-in effect:
When heating for the first time above 200 °C, some alloys (e.g. Alloy A20, Alloy L) experience a one-off change
in the material properties (e.g. specific resistance).
The cold resistance of the heating element is reduced by about 2… 3 %. But this small change in resistance gen-
erates a zero point error of 20…30 K. Therefore the zero point must be corrected after heating the first time, i.e.,
NOTE
ROPEX recommends the configuration “Alarm relay contact opened by alarm” in combination
with contactor Kb to switch off the load in the event of a fault. As a result, the interruption of the
wire (cable breakage) between the alarm relay of the RESISTRON
®
Temperature Controller
and the alarm signal relay will be monitored.
0
5
1 2
3
4
6
7
8
9
AU
X
CON
FIG
URA
TIO
N
ALARM
O
UTP
UT
ENER
GIZ
ED
(A T
AL
AR
M )
DE-E
NE
RG
IZ
ED
Alarm relay contact
opened by alarm
Alarm relay contact
closed by alarm.
(factory setting)
RES-5008
Alarm relay
13
12
0 V
< 30 V
14
Contactor Kb
