Two-point user calibration

The vendor calibration is to be deactivated via index (0x80n0:0B).

Up to FW version 07 the deactivation of the vendor calibration only results in the vendor gain being set to 214 (fixed-point representation for 1.0). The vendor offset remains unchanged and is still included. This results in the following with vendor calibration deactivated:

Two-point user calibration 1:

Since the last part of the term is constant, a user calibration can be performed despite the unavoidable influence of the vendor offset. The influence of the vendor offset can thereby be fully compensated.
The following method is to be applied:

Carry out two reference measurements with Y1(X1) and Y2(X2). Then the following applies:

Two-point user calibration 2:

GU and OU are to be rounded to the nearest whole number and entered in index 0x80n0:18 and index 0x80n0:17.

X

Raw value (0x80nE:01)

OV:

Vendor Offset (index depends on the mode, see chapter Vendor calibration)

GU:

User Gain (0x80n0:18)

OU:

User Offset (0x80n0:17)

gf:

Gain as a floating value

OR:

Offset as a raw value

Xn:

Measured raw value with reference measurement n

Yn:

Reference value in 1/256 Ω

Yint:

Output value in 1/256 Ω prior to the linearization

Note

Yn: Use of the raw value

Since the resistance value in index 0x8xxE:02 overflows, the raw value in index 0x8xxE:01 is used for Yn.

Further Information