LG Electronics 120S user manual Response format NAK response

Chapter 8 Communication Functions

(4) Response format (NAK response)

Format name	Header	Station No.	Command	Command type
Ex. of frame	NAK	H20	R(r)	SS
ASCII value	H15	H3230	H52(72)	H5353

Error code

(Hex 2 Byte)

H1132

H31313332

Tail	Frame check
ETX	BCC
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

K120S main unit

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	Number of	Variable
				type	blocks	length
Ex. of frame	ENQ	H01	r	SS	H02	H05
ASCII value	H05	H3031	H72	H5353	H3032	H3035

Format

name

%MW20

H254D57

3230

Device	Format name	Tail	Frame
length			check
H06	%PW001	EOT	BCC
H3036	H25505730	H04
	3031

②For ACK response after execution of command(PC ← MASTER-K120S main Unit)

Format name	Header	Station No.	Command	Command	Number of	Number of	Data	Number of	Data	Tail	Frame
				type	blocks	data		data			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

8-11