Modbus slave link message parameters – Rockwell Automation AADvance Controller Configuration Guide User Manual
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Modbus Slave Link Message Parameters
Each Modbus slave link message has a set of parameters as detailed in the table.
Table 33:
Modbus Slave Link Message Parameters
Description
Value(s)
Default
Remarks
Command
Read Inputs;
Read Coils;
Write Coils;
Read Input Registers;
Read Holding Registers;
Write Holding Registers
Read Coils
Command type specifies
the direction of the
message
Slave
1 to 65,536
1
Range of values usable
depends on the slave
device
Master Mimic
Depends on command —
see table below
Various
Master
1 to 65,536
1
Count
1 to 2,000 for a Write Coils
message;
1 to 125 for a Write Holding
Registers message
Control
1 to 65,536,
or 0 to disable
The address of a control
register (coil) (†)
0 = enabled
1 = disabled
Note: (†) The 'remarks' here summarize the values allowed for the contents of the
register.
Table 34:
Master Mimic Values for Modbus Slave Link Messages
Command
Master Mimic Value(s)
Default
Remarks
Read Inputs
Coils
Coils
Read Coils
Coils
Coils
Write Coils
Coils;
Inputs
Coils
Read Input Registers Holding Registers
Holding
Registers
Read Holding
Registers
Holding Registers
Holding
Registers