MR MESSKO MT-ST Compact, Operating Instructions Manual

Page: 72 / 92

5 Installation and commissioning
72 BA5831400-00 EN
5. Remove the measuring device.
6. Put the bridge back in terminals and and tighten the lock screws.
Since you are not working with the actual heating current dur-
ing this setting process, we recommend a second calibration
before commissioning.
Temperature gradient calibration before commissioning:
Example:
Displayed temperature without current source: 40 °C
Nominal secondary transformer current: 1.9 A
Required gradient: 26 K
Temperature display after gradient adjustment: 40 °C
+ 26 K = 66 °C
ü The thermometer is mounted on the transformer.
1. Note the temperature currently shown on the thermometer (e.g. 40 °C).
2. If a constant temperature cannot be ensured, we recommend taking the
temperature sensor out of the thermometer pocket and placing it in a ther-
mometer calibration bath. Set the calibration bath to a temperature of
40 °C, for this example.
3. Connect a current source to terminals and of the thermometer. Set
the nominal secondary transformer current specified by the transformer
manufacturer (e.g. 1.9 A) on the current source.
4. Wait until the temperature display stops changing (approx. 15 minutes).
5. Compare the temperature display to the previously calculated value (in
this example, 40 °C + 26 K = 66 °C).
6. If the required temperature value is not reached on the thermometer dis-
play, use the adjustment screw of the potentiometer to readjust (take the
heating and cooling time of approx. 15 minutes into account).
7. If the displayed temperature remains at the required value constantly over
a period of 30 minutes, the calibration is complete.
8. Reinstall the temperature sensor in the thermometer pocket.