Jump to content

Recommended Posts

Hi all

 

I am using a V430-j-t38 with add on Ethernet card.

 

 

The problem I am experiencing is with the built in Com port, I have set the dip switches to rs485 and  we use this port as a Modbus slave from a Motorola Ace3600,

 

I am being sent a Vector of values in MI 141,142,143

 

The problem is my plc interprets the information wrong and loads all the data into MI 141 as 19456

when at the moment it should be 36, 1796 & 666 but the current values it should send don't really matter I seem to just get 19456

 

The data being sent doesn't seem to be a problem nor does the PLC really because through testing we have tried,

 

A samba running same code as v430 slave but with add on rs485 port - works correctly

The V430 using an rs485 instead of Ethernet add on port - works correctly

The samba as master sending data to the V430 through inbuilt port also works correctly

 

The problem only is when using the inbuilt port connecting to the Motorola PLC

Can anyone make any suggestions?

 

I know its not the Modbus config or com init blocks because it is receiving data its just messing up the values somewhere

 

Thanks Kieran

 

Share this post


Link to post
Share on other sites

How are you verifying the value in MI 141?

 

It's strange to hear that the Samba acting as the master is successful while using the Motorola PLC is not. Does the Motorola have any special settings for serial opposed to Ethernet?

 

Is that value being used or modified in the Motorola program where it can change from 36 to 19456 though another operation?

Share this post


Link to post
Share on other sites

How are you verifying the value in MI 141?

 

It's strange to hear that the Samba acting as the master is successful while using the Motorola PLC is not. Does the Motorola have any special settings for serial opposed to Ethernet?

 

Is that value being used or modified in the Motorola program where it can change from 36 to 19456 though another operation?

By verifying I assume you mean looking at the value? I have the MI in a watch list and there are no actions set for that MI yet it will be stored into my program MIs when working correctly

 

it seems that the Motorola is sending the values correctly because the add-on rs485 port works correctly on both the samba and v430 and get the 3 MIs filled correctly

its just when using the built in port I have issues

For testing I made up a basic program for both plcs and just swapped them over to see the results so no changes were made to the Motorola in between using devices

 

 

I took a photo of the hex returned in info modes serial monitor and it was 1e 10 00 8d 00 03 12 4c on tx and rx but that doesn't means much to me

Share this post


Link to post
Share on other sites

This is a strange issue that I have not heard before. If the code has been verified on other units, and the add-on RS485 works, I do not see a reason why there would be any problem with using the main connection.

 

Do you have another V430 that exhibits the same issues?

 

Have you used any different RS485 cables between the main COM port and the add on COM port that worked correctly?

 

For further assistance please contact support@unitronics.com.

Share this post


Link to post
Share on other sites

This is a strange issue that I have not heard before. If the code has been verified on other units, and the add-on RS485 works, I do not see a reason why there would be any problem with using the main connection.

 

Do you have another V430 that exhibits the same issues?

 

Have you used any different RS485 cables between the main COM port and the add on COM port that worked correctly?

 

For further assistance please contact support@unitronics.com.

I think I might have it!

the add on port is an v100-rs4x so its isolated where the built in one is not, I am now trying to find an rs485 isolator to try in the bus to the plc and see if that helps otherwise I will just have to swap up to a v700 and use an add on rs485 port since the Ethernet is inbuilt.

 

Thanks for your help

Share this post


Link to post
Share on other sites

Hello

You also changed the com init in your Logic to com1 and also in the modbus config fb?

This because the units that worked used com2.

On the other hand when com init is wrong you would not receive anything.

I know this sounds like stupid question but one can sometimes forget too take a look at the most simple things.

Succes

Kind regards

Henny

Share this post


Link to post
Share on other sites

Hi Kezza,

 

 

I have set the dip switches to rs485

 

 

have you got the termination set correctly on the 430?   Perhaps the mix of different manufacturers doesn't work properly if the net layout isn't perfect.  I would have thought you would have the DIPs 1-6 off on on off on on.  Maybe this is why it works with the add-on cards etc as you have missed them being set ok.

 

cheers,

Aus

Share this post


Link to post
Share on other sites

Thanks for all your replies.

I have since installed a replacement v430 that has fixed the issues

Modbus up and running with correct values into correct MIs

I now have the fun of explaining to the masters that their 2 min scan update time is quite hard to work with....

Clients love using our remote operator though over fiber internet, just like being onsite

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...