Function Code 15 ($0F) – Write Multiple Coils
Description
Modbus function code ($0F) is a request to write multiple coils. This will write multiple digital outputs to an
RIO configured as a slave.
Operating as a master
The function code of the response can be queried with the _MW command. If an exception occurred, the
exception code of the response can be queried with _MW1.
Example:
Normal Response
Exception Response
_MW results in $0F
_MW results in $8F
_MW1
contains
$01
or
$02
Ways to use function code 15 with Galil commands:
1. MB command in raw packet mode
2.
MB command with Modbus function code 15
Operating as a slave
The RIO will accept a write multiple coils request with a starting address ranging from $0000-$000F,
referencing digital outputs 0-15. The RIO will accept a request for up to all 16 of its digital outputs, or
$0001-$0010.
The RIO will respond with function code $0F, a starting address field which matches the starting address
field of the request packet, and a quantity of outputs which matches the quantity of outputs field of the
request packet.
RIO-47xxx
Chapter 3 Communication
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