Chapter 6. Serial I/O, SNP & RTU Protocols
Message (05): Force Single Output
Format:
Query:
▪
An Address of 0 indicates a broadcast request. All slave stations process a broadcast re-quest and
no response is sent.
▪
The function code is equal to 05.
▪
The Point Number field is two bytes in length. It may be any value less than the highest output point
number available in the attached CPU. It is equal to one less than the number of the output point to
be forced on or off.
▪
The first byte of the Data field is equal to either 0 or 255 (FFH). The output point specified in the Point
Number field is to be forced off if the first Data field byte is equal to 0. It is to be forced on if the first
Data field byte is equal to 255 (FFH). The second byte of the Data field is always equal to zero.
Response:
▪
The normal response to a force single output query is identical to the query.
Note: The force single output request is not an output override command. The output specified in
this request is ensured to be forced to the value specified only at the beginning of one sweep
of the user logic.
240
Func
Address
05
Func
Address
05
Normal Response
Figure 56: RTU Force Single Output Message Format
PACSystems* RX7i, RX3i and RSTi-EP CPU Reference Manual
Point
Error Check
Data
Number
00H
Hi
Lo
Hi
Lo
Query
Point
Error Check
Data
Number
00H
Hi
Lo
Hi
Lo
GFK-2222AD