Figure 4.15 command frame, Figure 4.16 response frame, Write variable address – Rockwell Automation 900 Temperature Controller Communications Functions - Series B User Manual

Page 73: Variable write, single/operation command -15, Variable write, single/operation command

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Publication 900-UM004D-EN-E - July 2010

Modbus Communications Procedure

4-15

Variable Write, Single/Operation Command

This function performs operations such as writing to the variable area (single)
and operation commands (communications writing, RUN/STOP, multi-SP,
AT execute/cancel, write mode, save RAM data, software reset, move to setup
area 1, move to protect level, auto/manual switch, initialize settings, alarm
latch cancel, invert direct/reverse operation, and program start.) Writing is
enabled in only the 2-byte mode.

Figure 4.15 Command Frame

Figure 4.16 Response Frame

Write variable address

Specify the address of the setting data that is to be written. For details
on addresses, refer to Communications Data for Modbus on page 5-1.
For an operation command, specify 0000 or FFFF.

CRC-16

1

1

2

2

H'06

Write data

2 bytes

Slave

address

Function

code

Write variable

address

CRC-16

1

1

2

2

H'06

Write data

2 bytes

Slave

address

Function

code

Write variable

address