LS Industrial Systems GLOFA GM7U Series - Command Command

Chapter 8. Communication Functions
8-11
(4) GM7U main unit response format (NAK response)
Format name Header
Station
No.
Command Command type
Error code
(Hex 2 Byte)
Tail Frame check
Frame (Ex.) NAK H20 R(r) SS H1132 ETX BCC
ACSII value H15 H3230 H52(72) H5353 H31313332 H03
Item Description
Error code Hex and 2 bytes (ASCII code, 4 bytes) indicate error type. For the details, see 8.1.8 Error codes.
Frame check
(BCC)
When command is lowercase(r), only one lower byte of the value resulted by adding 1 byte each
to the ASCII values from NAK to ETX is converted into ASCII and added to BCC.
(5) Example
• This example assumes when 1 WORD from %MW20, and 1 WORD from %QW0.0.1 address of station No.1 are read.
H1234 is entered in %MW20, and data of H5678 is entered in %QW0.0.1.
① Computer request format (PC → GM7U main unit)
Format
name
Header
Station
No.
Command
Command
type
Number
of
blocks
Variable
length
Format name
Device
length
Format name Tail
Frame
check
Frame ENQ H01 r SS H02 H05 %MW20 H08 %QW0.0.1 EOT BCC
ACSII
value
H05 H3031 H72 H5353 H3032
H3035 H254D573230 H3038
H25515730
2E302E31
H04
② For ACK response after execution of command (PC ← GM7U main unit)
Format
name
Header
Station
No.
Command
Command
type
Number
of
blocks
Variable
length
Format
name
Device
length
Format
name
Tail
Frame
check
Frame ACK H01 r SS H02 H02 H1234 H02 H5678 ETX BCC
ACSII
value
H06 H3031 H72 H5353 H3032
H3032 H31323334 H3032 H35363738 H03
③ For NAK response after execution of command (PC ← GM7U main unit)
Format name Header Station No. Command Command type Error code Tail Frame check
Frame NAK H01 r SS Error code (2) ETX BCC
ACSII value H15 H3031 H72 H5353 Error code (4) H03
※ Frame check BCC is automatically operated.
GM7U main unit