PLC LOLETTE LE3U (FX3U) 48MR as Modbus Master. Trouble

LE3U, LE200, CF2N,EX1S,GX1S PLC, Smkoon, op320 etc.
manual from www.xueplc.com
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alexey.nightingale
Posts: 3
Joined: Mon Sep 03, 2018 11:30 am

PLC LOLETTE LE3U (FX3U) 48MR as Modbus Master. Trouble

Post by alexey.nightingale » Wed Sep 05, 2018 3:31 pm

Hi there.

Need some help with commissioning of Modbus RTU protocol. Better if it will simple examples. I've already used examples from archive FK3U.rar and it wasn't helpful :?

TASK.
1. PLC LE3U (FX3U) 48MR is acting as master with parameters (for example): 9600 Kbps,8 bit, no parity, 1 stop bit.
2. Any devices (Modbus RTU such as frequency conversters, PLC of another manufacturer and etc) are actining as slave.

GOAL.
1. Simple code (LAD) that will describe reading of bit (Coil 0) from a slave (address 2).
2. Simple code (LAD) that will describe writing of bit (Coil 0) into a slave (address 2).
3. Simple code (LAD) that will describe reading of holding register (HR 0) from a slave (address 2).
4. Simple code (LAD) that will describe writing of holding register (HR 0) from a slave (address 2).

alexey.nightingale
Posts: 3
Joined: Mon Sep 03, 2018 11:30 am

Re: PLC LOLETTE LE3U (FX3U) 48MR as Modbus Master. Trouble

Post by alexey.nightingale » Wed Sep 12, 2018 1:35 pm

I've tried any variants and modbus still doesn't work. If you have any suggestions, please suggest.

Here is short part of a code for communication with modbus slave device (address 2).

Detail description of the code:
***M8002 - Start-up pulse merker
H0C091 to D8120 - 1100000010010001 - 8bit, no verification, 1 stop bit, 19200 kbps, no start/stop symbols, free communication RS
K1 to D8121 - 1 - RS485 communication local station number (master address - 1)
K100 - 100 - RS485 time-out time setting (1000ms)
RST M8120 - 0 - Implementation of RS for the RS485
RST M8161 - 0 - 16 bit data format

***M8000 - Runnig programm merker (always 1 in runnig mode)
MOV H203 to D0 - Highb 0&02 and Lowb 0&03 - Highb is slave address (slave address - 2), Lowb is command for slave
(03 read holding register)
MOV H0 to D1 - 0 - Start address for reading in slave
MOV H1 to D2 - 1 - Quantity of reading data
SET M8122 - 1 - Request for data transmission
RS D0 K3 D20 K3 - - Telegramm D0D1D2 for slave. Answer from slave will be stored in D20D21D22

***M8123 - - Flag of condition, data are received. Should be reset after auto-set
***M8129 - - Flag of condition, time-out fault.
Attachments
Ladder_RS485.jpg
Ladder_RS485.jpg (66.32 KiB) Viewed 1244 times

Oymyakon
Posts: 1
Joined: Tue Sep 04, 2018 1:44 pm

Re: PLC LOLETTE LE3U (FX3U) 48MR as Modbus Master. Trouble

Post by Oymyakon » Wed Sep 26, 2018 3:14 pm

Hi,
Has anyone got the Modbus master command working on the RS485 port? I am keen to get this working.
Cheers
Paul.

alexey.nightingale
Posts: 3
Joined: Mon Sep 03, 2018 11:30 am

Re: PLC LOLETTE LE3U (FX3U) 48MR as Modbus Master. Trouble

Post by alexey.nightingale » Wed Sep 26, 2018 5:10 pm

Hi Oymyakon.

Problem solved. PLC is working in both modes: as master and as slave.

Later, I guess in a week, I'll attach here samples with short code and description for that. Now I'm on vacation.

And also try to use samples from here (official from seller): https://drive.google.com/open?id=0B874X ... zhDZ2ZNdGM

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