LG MASTER-K 120S Series User Manual page 201

Chapter 8 Communication Functions
(4) Response format (NAK response)
Format name Header
Ex. of frame NAK
ASCII value
Item
BCC
Error code
(5) Example
This example supposes when 1 WORD from M20 and 1 WORD from P001 address of station No.1 are read and BCC value
is checked. Also it is supposed that H1234 is entered in M20, and data of H5678 is entered in P001.
① Computer request format (PC → MASTER-K120S main Unit)
Format name Header
Ex. of frame ENQ
ASCII value H05
② For ACK response after execution of command(PC ← MASTER-K120S main Unit)
Format name Header
Ex. of frame ACK
ASCII value H06
Station No. Command
H20
H15 H3230 H52(72)
When command is lowercase(r), only one lower byte of the value resulted by adding 1
Byte each to ASCII values from NAK to ETX is converted into ASCII and added to BCC.
Hex and 2 bytes(ASCII code, 4 bytes) indicate error type. For the details, see 8.1.8 Error
codes.
Command
Station No. Command
type
H01 r SS
H3031 H72 H5353
Command
Station No. Command
type
H01 r SS
H3031 H72 H5353
Command type
R(r) SS
H5353
Explanation
Number of Variable Format
blocks length name
H02 H05 %MW20
H254D57
H3032 H3035
3230
Number of Number of
Data
blocks data
H02 H02 H1234
H3032 H3032 H31323334 H3032 H35363738 H03
8-11
Error code
Tail
(Hex 2 Byte)
H1132 ETX
H31313332 H03
K120S main unit
Device
Format name
length
H06 %PW001 EOT
H25505730
H3036
3031
Number of
Data
data
H02 H5678 ETX
Frame check
BCC
Frame
Tail
check
BCC
H04
Frame
Tail
check
BCC