40 Process Image
WAGO-I/O-SYSTEM 750 XTR
750-563/040-000 2AO 0/4-20mA/ 6-18V DC/ 16Bit /XTR
Manual
Version 1.3.0
4.4.4
Step 4 – Y
3
Limit Control
The limit control monitors whether the Y
2
value is in DAC format in the required
value range. This value range is defined by the parameter underrange limiting
value (UNR) and the overrange limiting value (OVR).
While determing the calibration values for the manufacturer or user calibration,
there should be no limit. This is achieved by configuring the overrange and
underrange limiting values to the maximum or minimum value (65535 or 0).
If you want to set the limits to defined analog output values, then these must be
determined either like the calibration values in step 5 or calculated from these.
Values must be input in raw data format!
The values for the lower and upper limiting value must be entered in raw data
format, i.e., if a user scaling is set, it must be taken into account for the entry of
the limiting values.
If in addition a number notation in the (+/
−
) range is selected, the limiting values
must be converted into equivalent values for a positive number range.
4.4.5
Step 5 – Y
DAC
Calibration
This level serves to calibrate an analog output range to the process data value
range. As parameters for the calibration, the I/O module only transmits the basic
value for the minimum value of the analog output range as offset. The basic
value for the maximum value serves to calculate a linear gain. The degree of the
gain is entered as amplification factor in register 37.
The gain factor is calculated as follows:
Gain
(A/H)K
= 8192*((BasicValue
max
- BasicValue
min
) / 65535)
Two calibration sets are provided for the I/O module. The sets are divided into
manufacturer and user calibration. Only one calibration set is ever active.
Calculation formula:
Y
DAC
= X
3
* Gain
(A/H)K
/ 8192 + Offset
(A/H)K
With activation of the user calibration, the analog output range can be selected
taking into account the operating mode. In reality, the possible minimum and
maximum analog output values lie a little below or above the specified analog
limits.