LG Electronics 120S user manual Input

Chapter 8 Communication Functions

3) Example program 2

It’s supposed that MASTER-K120S main unit is the master and it reads Coil Status of the station no. 17, a Modicon product. The master reads status of the input contact 10197 ~ 10218 of the slave station no. 17.

The input contact of the slave station is supposed to be as follows and the data that are read is saved in M015.

Input	10220	10219			10218	10217	10216	10215			10214	10213	10212	10211		10210	10209
Status	X	X		1		1	0	1		0		1	1	1		0	1
Hex			3						5						D
Input	10208	10207			10206	10205	10204	10203			10202	10201	10200	10199		10198	10197
Status	1	0		1		1	1	0		1		0	1	1		0	0
Hex			B						A						C

•The status of input contact 10219,10220 are redundancy.

•Data is sent starting from the low bit by byte unit. If the deficient bit of a byte is filled with 0. An example of sending the

above data is as follows. Example 2) AC DB 35

①

②

③

④

① : It designates slave station and function code ( No. of station : h11(17) , function code : h02 )

②: Address setting

Address ‘0’ at MODBUS protocol means address ‘1’ actually .So if you want to designate address ‘10197’ , write address ‘10196’

③ : Reading number setting ( Reading number is 22 from 10197 to 10220.)

④ : This is MODBUS Communication instruction.

The data transmission starts lower byte. The remnant part of byte is filled with ‘0’

⑤Stored data at D200,D201 are :

Device	Stored data
D200	h	AC	DB
D201	h	00	35

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