Batch Controller RA33
Commissioning
Hauser
39
Transmission of values
The actual Modbus TCP protocol is between Layers 5 and 6 in the ISO/OSI Model.
To transmit a value, 3 registers of 2 bytes each are used (2 bytes 4-byte float). In the setup,
you can configure which register is to be written with which value. The most important/most com-
mon values are already preconfigured.
Validity and limit value information are encoded in the status byte.
On receipt of the request from the master, the required start register and the number of registers to
be read are sent to the batch controller. Because a measured value always requires three registers,
the start register and the number must be divisible by 3.
From the master to batch controller:
ga fk r1 r0 a1 a0 c1 c2
Response from the batch controller for successful request:
ga fk az s1 s0 w3 w2 w1 w0 s1 s0 w3 w2 w1 w0 . . . . . s1 s0 w3 w2 w1 w0 c1 c0
Response from Batch Controller for unsuccessful request:
ga fk fc c0 c1
Register 000
Status of first measured value (16-bit integer, high byte first)
Register 001 to 002
First measured value (32-bit float, high byte first)
16
6
5
4
3
2
1
not used
0
0
0
0
ok
0
0
0
1
Open circuit
0
0
1
0
Over range
0
0
1
1
Under range
0
1
0
0
Invalid measured value
0
1
1
0
Replacement value
0
1
1
1
Sensor error
1
Lower limit value violated
1
Upper limit value violated
1
Counter overflow
ga
Slave address (1 to 247 )
fk
Function, always 03
r1 r0
Start register (high byte first)
a1 a0
Number of registers (high byte first)
c0 c1
CRC checksum (low byte first)
ga
Device address
fk
Function, always 03
az
Number of bytes of all subsequent measured values
s1 s0
Status of first measured value (16-bit integer, high byte first)
w3 w2 w1 w0
First measured value in 32-bit float format, high byte first
s1 s0
Status of second measured value (16-bit integer, high byte first)
w3 w2 w1 w0
Second measured value (32-bit float, high byte first)
s1 s0
Status of last measured value (16-bit integer, high byte first)
w3 w2 w1 w0
Last measured value (32-bit float, high byte first)
c0 c1
CRC checksum, 16-bit (low byte first)
ga
Device address
fk
Requested fu 80hex
fc
Error code
c0 c1
CRC checksum, 16-bit (low byte first)
