Connect Twido with M340 (Modbus)

hi mates, i want to connect my twido with a m340
i use modbus protocol RS-485
my cable's properties are:
twido mini Din - m340 RJ-45
1 - 4
2 - 5
7 - 8
8 - 7

and modbus parametres are:
-parity Even
-rtu
-9600 bauds
-stop bit 1

and here is serial port of twido


and m340's port



am i doing something wrong??
because it doesnt work....
any ideas??

Two things - simplify to start and use just two wires.

Per M340 documentation:

The pins used by the RS 485 serial link are as follows:
z Pin 4: D1 signal
z Pin 5: D0 signal
Pins 7 and 8 are used solely to supply power to human-machine interfaces via the
serial link

Do you need the power pins? If not, disconnect them.

So I would try:

1 - 4
2 - 5

if this doesn't work, swap one pair:

1 - 5
2 - 4

Failing that, I set up a PC with rS485 adapter and make sure each one works there directly to the PC.

If you use Twido's programming port, then you have to connect pin5 (DPT) to 7 (0V). If you don't connect it to 0v, port is on programming mode and modbus communication won't work.

so, probably

1 - 4
2 - 5

5
|
7

if communication don't work swap A and B signals, as robertkjonesjr wroted.

And disconnect power cables, now you have short circuit from +5V to ground.

Hi! I have a some problem with TWDLCDA24DRF PLC. Does anybody halp me?
If somebody have this PLC, please open the cover and on the bottom layout you can see some transistor. It marked (Q18) on the layout. I want to know the number of this transistor. It is burned in my TWIDO.

Lare said:

If you use Twido's programming port, then you have to connect pin5 (DPT) to 7 (0V). If you don't connect it to 0v, port is on programming mode and modbus communication won't work.

so, probably

1 - 4
2 - 5

5
|
7

if communication don't work swap A and B signals, as robertkjonesjr wroted.

And disconnect power cables, now you have short circuit from +5V to ground.

Click to expand...

fantastic Lare!!
it worked perfect, thanks a lot!!!

You are welcome. Nice to hear that it helped