Modbus Data Reference; Supported Modbus Function Codes; Modbus Slave Id Relationship - Proconx GCP-MG User Manual

Chapter 6. Modbus data reference
This chapter describes how GCP-30 and LS 4 data values are organized in logical blocks
and accessed via Modbus.
The GCP-MG supports the Modbus function codes 03, 04, 06 and 16. A maximum of
100 16-bit words can be requested with Modbus command 04. This makes it possible to
read the complete data set of a GCP-30 or LS 4 unit with a single Modbus transaction.
Modbus
function code
04
03
06
16
Table 6.1: Supported Modbus function codes
The GCP-MG emulates a virtual Modbus slave device for each GCP-30 and LS 4 unit
connected to the CAN bus. This simplifies management of PLC and SCADA variable tag
tables, as the Modbus start address is identical for all GCP-30 and LS 4 units.
The following tables show the relation of an individual unit with the Modbus slave ID
and the Modbus register range:
Unit
GCP-30 #1
GCP-30 #2
GCP-30 #3
GCP-30 #4
GCP-30 #5
GCP-30 #6
GCP-30 #7
GCP-30 #8
GCP-30 #9
GCP-30 #10
GCP-30 #11
GCP-30 #12
GCP-30 #13
GCP-30 #14
GCP-30 #15
GCP-30 #16
LS 4 #1
LS 4 #2
LS 4 #3
LS 4 #4
LS 4 #5
UMGCPMG-2201
Function name
Read input registers
Read holding registers
Write single register
Write multiple registers
Modbus Modbus read
slave ID address range
1 3:0001-3:0100
2 3:0001-3:0100
3 3:0001-3:0100
4 3:0001-3:0100
5 3:0001-3:0100
6 3:0001-3:0100
7 3:0001-3:0100
8 3:0001-3:0100
9 3:0001-3:0100
10 3:0001-3:0100
11 3:0001-3:0100
12 3:0001-3:0100
13 3:0001-3:0100
14 3:0001-3:0100
15 3:0001-3:0100
16 3:0001-3:0100
17 3:0001-3:0100
18 3:0001-3:0100
19 3:0001-3:0100
20 3:0001-3:0100
21 3:0001-3:0100
Access Max. number of 16-bit
words per transaction
read 100
write 3
write 1
write 3
Modbus write Modbus floating point
address range address range
4:0001-4:0003 3:1001-3:1076
4:0001-4:0003 3:1001-3:1076
4:0001-4:0003 3:1001-3:1076
4:0001-4:0003 3:1001-3:1076
4:0001-4:0003 3:1001-3:1076
4:0001-4:0003 3:1001-3:1076
4:0001-4:0003 3:1001-3:1076
4:0001-4:0003 3:1001-3:1076
4:0001-4:0003 3:1001-3:1076
4:0001-4:0003 3:1001-3:1076
4:0001-4:0003 3:1001-3:1076
4:0001-4:0003 3:1001-3:1076
4:0001-4:0003 3:1001-3:1076
4:0001-4:0003 3:1001-3:1076
4:0001-4:0003 3:1001-3:1076
4:0001-4:0003 3:1001-3:1076
4:0003 3:1001-3:1034
4:0003 3:1001-3:1034
4:0003 3:1001-3:1034
4:0003 3:1001-3:1034
4:0003 3:1001-3:1034

Modbus data reference

Data table/block
3:0000
4:0000
4:0000
4:0000
CAN ID
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
33