Calibrating Measured Values; Example Of Determining Gain And Offset; Table 63: Variable Legend - Calibrating Measured Values - WAGO 750-564 Manual

WAGO-I/O-SYSTEM 750
750-564 4AO U/I
9

Calibrating Measured Values

The manufacturer calibration serves to compensate tolerances in electronic
components of the I/O module. User calibration allows you to compensate for the
tolerances of electronic components of both the I/O module and connected
devices and to take into account factors such as component age and different
ambient temperatures at the installation site.
User calibration by channel required!
Perform the calibration for each channel individually to achieve the greatest
possible measurement accuracy for each channel.
The variables in the following equations have the following meaning:
Table 63: Variable Legend – Calibrating Measured Values
Variable
m
b
x1
x2
y1
y2
The "Gain" and "Offset" values are required in order to perform user calibration.
The calibration gain indicates the factor by which the process value is amplified.
The calibration offset indicates the offset of the process value on the y axis.
The following general calibration equation applies:
y = (x + b) × m
The general calibration equation yields the following two equations for calculating
the two values sought:
Calibration gain: m = (y2 – y1) / (x2 – x1)
Calibration offset: b = y1 – (m × x1)
9.1.1

Example of Determining Gain and Offset

A two-point calibration method is used.
Perform the following steps in WAGO-I/O-CHECK:
1. Select a channel, as well as a signal type and the resolution, under
Channel Settings.
In this example, signal type "0 ... 10 V" (16-bit resolution) has been
selected.
Calibrating Measured Values
Explanation
Calibration gain (gain factor)
Calibration offset (offset)
Expected output voltage/output current 1
Expected output voltage/output current 2
Process value 1
Process value 2
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Manual
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