Calibrating Measured Values - WAGO 750-489 Manual

4ai rtd/tc/strain gauge ex i, 4-channel analog input, rtd/tc/strain gauge, intrinsically safe for wago-i/o-system 750 series
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WAGO-I/O-SYSTEM 750
750-489 4AI RTD/TC/Strain Gauge Ex i
9

Calibrating Measured Values

The precision that can be achieved in temperature measurement depends on the
following properties:
The accuracy of the transducer in the RTD/TC module
The accuracy of the linearization in the RTD/TC module
The quality of the electrical contact points
The quality of the thermal contact points
The accuracy class of the thermal sensor and compensating lines
The thermal stability in the environment of the RTD/TC module
The first two issues are quality characteristics of the WAGO product; all other
properties are up to the user.
For the RTD/TC module, WAGO offers the option of using the WAGO-IO-CHECK
calibration dialog to compensate tolerances throughout the entire measurement
chain. This requires reference values to be available for temperatures of the
object to be measured.
Example 1
Requirements:
The WAGO node must be installed in the control cabinet; the temperature
in the control cabinet must have settled and be constant.
A thermocouple line must be laid up to the measuring point, but not yet
welded on there.
1.
Connect a calibrator to the open ends of the thermocouples.
2.
Use WAGO-IO-CHECK to calibrate the equipment via this calibrator.
3.
Remove the calibrator.
4.
Weld the thermocouple and secure it to the measuring point.
Example 2
Requirements:
The WAGO node must be installed in the control cabinet; the temperature
in the control cabinet must have settled and be constant.
A thermocouple line must be laid up to the measuring point.
The temperature of the object to be measured must be known precisely at
at least two points (e.g., eutectic phase changes => solid and liquid lines)
1.
Calibrate to these points.
The resulting calibration values are stored permanently in the I/O module.
Each supported sensor type has its own storage space available.
Calibrating Measured Values 149
Version 1.1.0, valid from FW Version 02
Manual

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