Chapter 6. Serial I/O, SNP & RTU Protocols
242
PACSystems* RX7i, RX3i and RSTi-EP CPU Reference Manual
GFK-2222AD
Message (07): Read Exception Status
Format:
Address
Error Check
Func
07
Query
Normal Response
Address
Data
Error Check
Func
07
Figure 58: RTU Read Exception Status Message Format
Query:
This query is a short form of request for the purpose of reading the first eight output points.
▪
An Address of zero is not allowed as this cannot be a broadcast request.
▪
The function code is equal to 07.
Response:
▪
The Data field of the normal response is one byte in length and contains the states of output points
one through eight. The output states are packed in order of number with output
point one’s state in
the least significant bit and output point eight’s state in the most significant bit.
