Chapter 3: Modicon PLCs Using Modibus Plus
37
The following is the format for a register reference:
[3rrr] or [4rrr]
rrr Controller reference number of the register.
The following is the format for a discrete input reference:
[1iiii]
iiii Controller reference number for an input reference.
The following is the format for a coil reference:
[0cccc]
cccc Controller reference number for a coil reference.
The following is the format for a register bit reference:
[3rrrr bb], [4rrrr bb], [3rrrr,bb], or [4rrrr.bb]
rrrr Controller reference number of the register.
bb Controller reference number of the bit position.
The bit positions are numbered 1 to 16, least significant to most significant.
Note:
The register number must be followed by a space or a period. Input register bit writes are not
allowed. Output register bit writes are not allowed (except for the 984-785 PLC).
The following is the format for a global data word read from a Modicon Controller:
[900rr]
rr Controller reference number of the register.
The following is the format for a global data bit read from a Modicon Controller:
[900rr bb] or [900rr.bb]
rr Controller reference number of the register.
bb Controller reference number of the bit position.
The bit positions are numbered from 1 to 16, least significant to most significant.
An Operator Station has 32 global words, numbered 1 to 32. The global data area on the Operator
Station can be written to and read from.
The following is the format for a global data word read from a Operator Station:
[GLBL,G00rr]
rr Operator Station reference number of the register.
