LG Electronics 120S user manual Continuous readingRrSB of device

Chapter 8 Communication Functions

③ For NAK response after execution of command(PC ← MASTER-K120S main Unit)

Format name	Header	Station No.	Command	Command type	Error code	Tail	Frame check
Ex. of frame	NAK	H01	r	SS	Error code (2 bytes)	ETX	BCC
ASCII value	H15	H3031	H72	H5353	Error code (4 bytes)	H03

2) Continuous reading(R(r)SB) of device

(1) Introduction

This is a function that reads the PLC device memory directly specified in accord with memory data type. With this, data is read from specified address as much as specified continuously.

(2) PC request format

Format name	Header	Station	Command	Command	Device	Device	Number of data	Tail	Frame
		No.		type	length		(Max. 128 Bytes)		check
Ex. of frame	ENQ	H10	R(r)	SB	H06	%MW100	H05	EOT	BCC
ASCII value	H05	H3130	H52(72)	H5342	H3036	H254D57313030	H3035	H04

Remark

1)Number of data specifies the number to read according to the type of data. Namely, if the data type of device is word and number is 5, it means that 5 words should be read.

2)Max. of %MW in number of data can be used up to 120(240bytes).

3)Protocol of RSB doesn't have number of blocks.

4)R(r)SB command of bit devices is not available.

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 ENQ to EOT is converted into ASCII and added to BCC.
Device length	This indicates the number of name's characters that means device, which is allowable up to
(Length of	16 characters. This value is one of ASCII converted from hex type, and the range is from
device name)	H01(ASCII value:3031) to H10(ASCII value:3130).
Device name	Address to be actually read is entered. This must be ASCII value within 16 characters, and in
	this name, digits, upper/lowercase, and '%' only are allowable to be entered.

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