doubts about the modbus vision 130 communication cable

[roghenr]

I have doubts about how to mount the modbus cable on vision 130.
The standard rj 11 connector has 4 contacts and the plc vision connector has 6 contacts.
The same happens with the vision 130 programming cable, can it be used for modbus?

Thanks.

[kratmel]

Best idea - use V100-17-RS4x isolated communication module for RS-485 connection. 6pin RJ 11 connector with two wire included. 

You can use modbus and Visilogic connection at the same time for debug (if V100-17-RS4x installed Port 1 -Visilogic connection, Port 2=Modbus communication).

You can also find 6pin RJ 11 (6P6C) connector for modbus DIY cable.

 

[roghenr]

thanks for the information it helped a lot.

 

Roghenr

[Ausman]

Look at this:   https://forum.unitronics.com/topic/6309-6-pin-rj45-screwed-terminal/#comment-25515

I use these, mainly for testing purposes, but mostly make up a cable using the 6P6C like Kratmel has shown.

cheers, Aus

 

[AlexUT]

14 hours ago, kratmel said:

You can use modbus and Visilogic connection at the same time for debug.

Hi All,

Keep in mind that both interfaces of the same PLC COM port (RS485 at pins 1 and 6, and RS232 at pins 2,3,4,5) use the same hardware (UART) inside PLC.

So you cannot use both RS485 at pins 1 and 6, and RS232 at pins 2,3,4,5 at the same time.

BREAK signal at RS232, will switch COM port to PCOM protocol (default 7, E, 1) and will collide with RS485 interface.

Conclusion:

To use both interfaces, one by one, you have to have 2 cables:

1. RS485 interface.

2. RS232 interface.

To make project download, you have to disconnect RS485 interface cable and connect RS232 interface cable.

If PLC is a MODBUS Master - it will send MODBUS requests, which may interfer with PCOM protocol.

To solve this - stop PLC from INFO mode to download project to PLC.

Then connect RS485 interface and power cycle PLC.

 

[Ausman]

7 hours ago, AlexUT said:

So you cannot use both RS485 at pins 1 and 6, and RS232 at pins 2,3,4,5 at the same time.

Therefore, please elaborate on the following:

I have never got around to trying this out, but it appears Kratmel has.  But from what you are saying it is not possible.

cheers, Aus

[kratmel]

I supplemented my previous post.

AlexUT is right that the same port cannot be used for two tasks at the same time.

It should be noted that, as Ausman wrote, physically simultaneous wiring is possible. However, the ports must actually work in turn - or connection via RS232 or RS485.

I specifically suggested the author of the topic put an additional port. This helps to avoid problems during debugging - whoever tries to do it with one port knows how inconvenient it is. Also for stable operation of modbus it is desirable to have galvanic isolation (V100-17-RS4x module with isolation, V130 port1 - not isolated).

[robert_v130]

Hello,

i ran into this r485 problem as well. My device is a v130 33t2, no extra cards.

My application needs only very few modbus rtu rs485 readings.  After that i want to return to the normal communication with visilogic pc.

So I am wondering: Is it possible in ladder to "undo" the modbus initialisation?  Or overwrite it somehow. I tried to do this with overwriting some SI and SB's, related to com1 status and settings.

An example of my effort: (disclaimer:-) i tried a lot, even if its not logical to do so..