Beckhoff EP3204, Documentation

Page: 41 / 92

Commissioning/Configuration
EP3204 and EP3314 41 Version: 2.2
6.2.5 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 2
14
(fixed-point representation for 1.0). The vendor offset remains unchanged and is still included. This results in
the following with vendor calibration deactivated:
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 Y
1
(X
1
) and Y
2
(X
2
). Then the following applies:
G
U
and O
U
are to be rounded to the nearest whole number and entered in index 0x80n0:18 and index
0x80n0:17.
X Raw value (0x80nE:01)
O
V
:
Vendor Offset (index depends on the mode, see chapter Vendor calibration [ } 34] )
G
U
: User Gain (0x80n0:18)
O
U
: User Offset (0x80n0:17)
g
f
: Gain as a floating value
O
R
: Offset as a raw value
X
n
: Measured raw value with reference measurement n
Y
n
: Reference value in 1/256 Ω
Y
int
: Output value in 1/256 Ω prior to the linearization
NOTE
Y
n
: Use of the raw value
Since the resistance value in index 0x8xxE:02 overflows, the raw value in index 0x8xxE:01 is used for Y
n
.