BECKHOFF FM33xx - Manual (Page 35)

Register description
30 FM33xx
TC-Plug - channel-specific register
description
Process variables R0: Unprocessed ADC value X_R
This register contains the unprocessed ADC value.
R1: Unprocessed ADC value for the cold junction compensation
R2: Temperature of the cold junction compensation
Unit: 1/10 degree Celsius, 16-bit signed int
R6: Diagnostic register
High byte: reserved
Low byte: status byte
R7: Command register
Commands:
0x0101
Offset adjustment with short-circuited input. An automatic offset
adjustment is carried out. At the same time the unprocessed ADC value
with which the cold junction compensation was carried out is kept in R23.
The corresponding inputs are to be short-circuited.
0x0102
Gain adjustment at 30 mV. An automatic gain adjustment is carried out on
the assumption that 30 mV is present at the corresponding input.
0x0103
Adjustment for temperature drift with short-circuited input. An offset
adjustment should be carried out at room temperature. This function is
called in order to take account of temperature drift. The comparison
temperature is entered into R24, and the corresponding coefficient into
R22.
R17: Calibration offset
In order to carry out a calibration, a zero is entered into R32 and R17, and
a comparison with 0 V is made. The process data value (in microvolts) is
multiplied by -1.9074, and entered into R17.
R18: Calibration gain
Value: [4096]
R19: Manufacturer scaling offset
Value: [0x0000]
R20: Manufacturer scaling gain
Fixed point number /256, so that 1 corresponds to a value of 256