CAN and RS485

[ivica]

I have connected V-350 with EXF-RC15 wia CAN com and that works perfectly. But I need also RS485 between V-350 and remote display and then my CAN crashes but only in direction V350 to EXF. In direction EXF to V350 works fine. Can somebody help me.

[Flex727]

Moved to VisiLogic Forum.

[kratmel]

Please post your Visilogic projects with normal and "corrupted" CAN configuraion with RS485 

[ivica]

In the meantime, I achieved communication in both directions V3350-EXFRC15, but I don't understand why the "check alive" routine on EXFRC15 shows me that the CAN connection is not established and only if I initiate RS485 in V350.  I am sending the EXF program with the CAN com check routine. 

EXF_unican_enc_gradex.vlp

[ivica]

I was wrong, I steel have the same problem. When I initialize 485 I cant send data from V350 to EXFRC15 via CAN, I can only receive it in V350. Can you please help me with any suggestion. 

[Ausman]

None of these might help, but are worth asking/checking.  Basics sometimes go astray.

1.  What baud rates are you using?  And what happens if you lower those rates?  I'd start at very slow ones to trial this, and then increase to the quickest stable one if the problem is cured.

2.  Ensuring that you are using correct termination resistor placement on everything?  If you can, please show your wiring in picture or drawing.

3.  Are you using the same power supply?  If not, is the remote's supply on the same phase, and - commoned?  As a matter of principle, I always have anything control run from the same phase throughout an installation.  In theory it makes no difference, but it's easy to do and avoids potential (you can read that both ways!) hiccouphs.

4.  All earths done correctly and linked?

cheers, Aus

[ivica]

I used 250kb baudrate in unicom and 5760 in RS485. It may be too quickly but in direction EXF to V350 it works fine. I will try to slow baudrate.

The termination resistors are placed as in photo.

I have tried with same and separate power supply but the result are the same.

Earts are done corretly.

In project I need 4 schaft encoders so I have to add EXF-RC15 for the 4th encoder. The two PLC are placed on the same rail.

Everything works fine until I added RS485 to V350.

shema.jfif

[kratmel]

In this doc on p.106 you can find why your V350 stop UNICAN

https://www.mikrocontroller.net/attachment/157952/VisiLogic_-_Communications.pdf

Please send quastion to  support@unitronics.com  about possible solution and post answer to topic.

I think Unit ID collision for RS485 communication appear.

[ivica]

I thought the same thing about ID collision. Is there any possibility of solving the problem.

[Ausman]

What Kratmel suggests makes sense but I have 120s on a Unican loop that has a 130 as the "master", and they are also using 485, and able to send and receive.  Not quite the same, but in some ways close enough.

I've now also opened your vlp and to me there are errors in that rung 2 should be separated out, and you actually have too much "control" of Unican going on.  Try changing your method along the lines of UniCan simply doing things on it's own.  I can't elaborate on this at present, lack time.   More later, once I can.  But I do know the Unican loop runs at  500K and the 485 on 9600.

And just confirming that everything works fine, but when you use 485 to talk to the remote display it goes haywire.

cheers, Aus