Dixell XEV22 communication with TM172

[otrotabi]

I have followed this video as a tutorial to setup modbus communication with a Dixell XEV22 electronic valve controller.

The information I have regarding how Dixell implements modbus on their devices is this: Dixell Modbus .

Dixell says an exception code 0x03 is thrown in case you want to access an invalid area and that you can only access 5 registers maximum at a time.

Questions: 

1) How do I access more registers ? Do I simply change the base input to the function ?

2) Is the exception code 0x03 what is reflected on the function output ? Is that the reason why I get a 3 sometimes ? 

3) I am willing to access more data from the controller, for example valve opening percentage. This information does not seem to be available following the input sensors registers. Anyone knows where to look for this information at the device ?

[LeTomas · Accepted solution]

Hi @otrotabi ,

In order to read more than 5 registers on the slave device i recommend you to use a "CASE **** OF" in order to make multiple readings/writings. In my example below i use it on ModbusTcp to access data of our TeSys Island:

In your case you must use the "sysMbRTU_FC**" but the logic will be the same.

Creating also a FB for that will be great if you are planning to re use it.

Best regards,

Leandro

[Bastian_Schmitz]

You have to ask Dixell for a more detailed list of modbus values. I integrate XEV22 ~10 years ago on a third party system via Modbus RTU befor I enter the happy world of TM17x. 

There shoudl be a documentation available with a list of all values reachable via modbus. Unfortunately I could not longer find this documentation.

If I look in my legavy programms it seems that Register Address 256...261...266 seems to be important.

In this values should be all information which you are normally need.

I would suggest to creat a continuous communication via Configuration and not via Programming. In my personal opinion that would be the best way for such a communication. For event based purpose I would suggest to do it via Programming. 

And finally I would suggest so far possible to use TM171VEVM4 or the new ones TM172EVEV** booth are much easier to integrate. An so far I see the Dixell drive could not  do anything which is not possible with TM17x drivers.

[otrotabi]

Thanks for your feedback. 

Yes, actually analog inputs are where they are supposed to be, registers 257/259/261, while 258/260/262 give information regarding the probes´ status. What I have not been able to find which is somewhat useful is valve opening percentage.

I think Dixell is not too willing to give that information, because they want to sell you their own solution, that being what they call Xweb. Xweb does not perform almost any control though, it is basically a supervision and gateway tool. 

I will ask anyway our local subsidiary for more data (Copeland is now the owner of Dixell as far as I know) but I am not sure whether they will give it.

I am afraid Schneider´s drivers are not available locally.