LG Electronics 120S user manual Example program, Coil Status

Chapter 8 Communication Functions

2) Example program 1

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 Coil 00020 ~ 00056 of the slave station no. 17. The Coil of the slave station is supposed to be as follows and the data that are read is saved in D1000

Coil	59	58			57	56	55	54			53	52	51		50		49	48	47	46		45	44	43	42		41	40
Status	X	X			X	1	1	0		1		1	0		0		0	0	1	1		1	0	1	0		1	1
Hex			1						B					0							E					B
Coil	39	38			37	36	35	34			33	32	31		30		29	28	27	26		25	24	23	22		21	20
Status	0	0		1		0	0	1		1		0	1		0		1	1	1	1		0	0	1	1		0	1
Hex			2						6							B					C					D

•The status of Coil 57, 58, 59 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 Following example 1. Example 1) CD B2 0E 1B

①

②

③

④

①It designates slave station and function code (No. of station : h11(17) , function code : h01)

② Address setting

-Address ‘0’ at MODBUS protocol means address ‘1’ actually .So if you want to designate address ‘20’ , write

address ‘19’

③Reading number setting ( Reading number is 37 from 20 to 56.)

④ This is MODBUS Communication instruction.

-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.

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

⑤Stored data at D1000,D1001,D1002 are :

Device	Stored data
D1000	h	CD	6B
D1001	h	B2	CE
D1002	h	00	1B

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