Chapter 7 Communication function
7-55
1
Reading of PLC STATUS (RST)
This is a function to read flag list such as operation status and error information of PLC.
1)
Request format(PC -> PLC)
Format
name
Header
Station No.
Command
Command type
Tail
Frame check
Frame(Ex.)
ENQ H0A R(r) ST EOT BCC
ASCII
value
H05 H3041
H52(72)
H5354 H04
9
BCC : When command is one of lower case(r), only one lower byte of the value resulted by adding 1 byte
each to ASCII values from ENQ to EOT is converted into ASCII and added to BCC.
2)
Response format(for PLC of ACK response)
Format
name
Header
Station No.
Command
Command type
STATUS data
(HEX 20 Byte)
Tail
Frame check
Frame(Ex.)
ACK
H0A
R(r)
ST
STATUS data format
ETX
BCC
ASCII
value
H06 H3041 H52(72) H5354
[
※
]
H03
9
Station number, commands, and type of command are the same as in computer request format.
9
BCC : When command is one of lower case(r), only one lower byte of the value resulted by adding 1 byte
each to ASCII values from ACK to ETX is converted into ASCII, added to BCC, and sent.
9
STATUS data format : This status format is converted into ASCII code of total 20 bytes in HEX. And Its
contents after converted to HEX data from ASCII code are composed as below.
[Table7.20] STATUS data Format
Data type
Flag name
Status data sequence(HEX data)
UINT PC_DEVICE_IDENTIFIER;
[Note 1]
H00(L) ~ H01(H)
Byte Logical;
[Note 1]
H02(Offset)
Byte Physical;
[Note 1]
H03
Byte _CPU_TYPE;
H04
Byte _VER_NUM;
H05