VIPA CP 240 RS232, Manual

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Manual VIPA System 200V Chapter 4 CP 240 - serial
HB97E - CP - Rev. 11/30 4-35
Modbus - Function codes
Modbus has some naming conventions:
Word =
Register
IN: "Input Register"
OUT: "Holding Register"
Bit =
Coil
IN: "Input Status"
OUT: "Coil Status"
•
Modbus differentiates between bit and word access;
Bits = "Coils" and Words = "Register".
•
Bit inputs are referred to as "Input-Status" and Bit outputs as "Coil-
Status".
•
Word inputs are referred to as "Input-Register" and Word outputs as
"Holding-Register".
Normally the access at Modbus happens by means of the ranges 0x, 1x, 3x
and 4x.
0x and 1x gives you access to digital Bit areas and 3x and 4x to analog
word areas.
For the CP 240 from VIPA is not differentiating digital and analog data, the
following assignment is valid:
0x: Bit area for master output data
Access via function code 01h, 05h, 0Fh
1x: Bit area for master input data
Access via function code 02h
3x: Word area for master input data
Access via function code 04h
4x: Word area for master output data
Access via function code 03h, 06h, 10h
3x 0001 3x 0002 3x 0003
1x 0001
1x 0002
1x 0003
IN
1x 0022
4x 0001 4x 0002 4x 0003
0x
0001
0x
0002
0x 0003
OUT
0x 0022
A description of the function codes follows below.
Naming
convention
Range definitions