Modbus Mapping For Read Register Services Fc3, Fc4, Fc23 - WAGO 750-8202/040-001 Manual

WAGO I/O SYSTEM 750 XTR
750-8202/040-001 PFC200 2ETH RS TELE XTR
9.4.4.3

Modbus Mapping for Read Register Services FC3, FC4, FC23

The table below outlines the mapping for the Modbus-reading, register-oriented
services:
• FC3 – Read Holding Registers,
• FC4 – Read Input Registers,
• FC23 – Read/Write Multiple Registers
Table 218: Modbus Mapping for Read Register Services FC3, FC4, FC23
Modbus Address
(hexadecimal values
in parentheses)
0 ... 999
(0x0000 ... 0x03E7)
1000 ... 1999
(0x03E8 ... 0x07CF)
2000 ... 4095
(0x07D0 ... 0x0FFF)
4096 ... 12287
(0x1000 ... 0x2FFF)
IEC 61131 Description
Address
%IW1000 ... Modbus Output:
%IW1999 1000 PFC input registers/words in the
2 kB Modbus output process image in
the PII.
Note: In this area, the read register
services return the content from the PII.
%QW1000 ... Modbus Input:
%QW1999 1000 PFC output registers/words in the
2 kB Modbus input process image in the
PIO.
Note on FC23:
Only the Read portion of this service can
be executed.
Inhibited to Modbus-only area for
register-oriented read access. Register-
based read services for this area are
acknowledged by the Modbus slave with
the Modbus exception code "ILLEGAL
DATA ADDRESS" (0x02).
No IEC 61131 Information and configuration registers:
address Not all Modbus addresses in this range
are valid.
Valid Modbus addresses are described
in the Section "WAGO Modbus
Registers".
Access to invalid addresses are
acknowledged by the Modbus slave with
the Modbus exception code "ILLEGAL
DATA ADDRESS" (0x02).
Note on FC23:
The Write portion of this service can only
be executed for registers that data can
be written to.
Version 1.2.0, valid from FW Version 03.01.07(13)
Modbus – CODESYS 2 297
Manual