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Chapter 8 Communication Functions
8-11
(4) Response format (NAK response)
Format name Header Station No. Command Command type
Error code
(Hex 2 Byte)
Tail Frame check
Ex. of frame NAK H20 R(r) SS H1132 ETX BCC
ASCII value H15 H3230 H52(72) H5353 H31313332 H03
Item Explanation
BCC
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.
Error code
Hex and 2 bytes(ASCII code, 4 bytes) indicate error type. For the details, see 8.1.8 Error
codes.
(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 Station No. Command
Command
type
Number of
blocks
Variable
length
Format
name
Device
length
Format name Tail
Frame
check
Ex. of frame ENQ H01 r SS H02 H05 %MW20 H06 %PW001 EOT BCC
ASCII value H05 H3031 H72 H5353 H3032 H3035
H254D57
3230
H3036
H25505730
3031
H04
② For ACK response after execution of command(PC ← MASTER-K120S main Unit)
Format name Header Station No. Command
Command
type
Number of
blocks
Number of
data
Data
Number of
data
Data Tail
Frame
check
Ex. of frame ACK H01 r SS H02 H02 H1234 H02 H5678 ETX BCC
ASCII value H06 H3031 H72 H5353 H3032 H3032 H31323334 H3032 H35363738 H03
K120S main unit