Publication 1766-RM001A-EN-P - October 2008
Protocol Configuration
617
Modbus Slave Memory Map
The modbus Memory map is summarized in and detailed in :
Modbus to MicroLogix Memory Map - Summary
Modbus
Addressing
Description
Valid MicroLogix Addressing
File Type
Data File Number Address
0001…4096
Read/Write Modbus Coil Data space
Bit (B) or Integer (N)
3…255
bits 0…4095
10001…14096
Read-Only Modbus Contact Data space
Bit (B) or Integer (N)
3…255
bits 0…4095
30001…30256
Read-Only Modbus Input Register space
Bit (B) or Integer (N)
3…255
words 0…255
30501…30532
Modbus Communication Parameters
Communication Status File
-
-
31501…31566
Read-Only System Status File space
Status (S)
2
words 0…65
40001…40256
Read/Write Modbus Holding Register space Bit (B) or Integer (N)
3…255
words 0…255
40257…41280
(1)
Read/Write Modbus Holding Register space Bit (B) or Integer (N)
3…255
words 0…255
of four Holding
Register files
41501…41566
Read/Write System Status File space
Status (S)
2
words 0…65
41793…42048
Read/Write Modbus Holding Register space Bit (B) or Integer (N)
3…255
words 0…255
of the last
Holding
Register file
(1) These addresses only become active when specially configured for expanded holding registers.
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