No Communication through Modbus RTU to an Ewon Flexy

Hi Everyone,

I am trying to connect a 3rd party device to our Modbus Flexy 201, through Modbus RTU, using the RS485 protocol.

These are the details:
|-|Serial Number of the comms card is 0786-2213-0051-06|
|-|Serial Number of the base is 1812-0135-21|
|-|Firmware version 13.0|

I have tested that the cable works through my laptop (so I can read the data Ok from the device). But when I plug the cable to the ewon flexy, I am getting a “No communication” Icon.

We have configured the MODBUS IO Server using the same parameters that I used when connecting through the laptop.

I have also configured one test tag.

And also the serial port 1 (which is where we are connected) is configured as RS485, half Duplex, Pol On, and the dip switches are placed in the right position.

In the event log, this is the error I’m getting:
21/09/2022 14:10:36 Serial SER1-<- Rx: Er/Wng -536893114 1201943 137

21/09/2022 14:10:34 Serial SER1-Tx 8: 01 03 00 00 00 01 84 0A

I’m also going to upload the backup.

Can anyone advice on where can the error be? Or if there is anything I am missing. Thanks.

EwonFlexy20x_Backup_21092022.tar (13 KB)

Hi @Sam4,

It appears to be a communications issue, but I’m unable to tell much more from the backup because it did not include the logs. Can you make another backup, this time checking the box “Include Support files”? Can you also make sure to enable debugging on the serial port?

You said that you were able to read data from the device using your laptop. Are you using a USB-to-serial adapter? If so, what type?

Which commands did you send with the laptop?

How long is the serial cable and is there just the one Modbus slave?

Hi Kyle,

Thanks for the response. I can confirm that the debugging on the serial port is enabled.
I have attached the backup you have requested.
EwonFlexy20x_Backup_21092022_withSupportFiles.tar (204 KB)

The cable is not super long, I would say 2 meters max 1.5-2meters.

We did use a USB-to serial adapter when we connected to the laptop. This is de model.

This is what we were reading the other day


We have solved it. You pointed us to the right direction. The USB adapter has a different pin-out than the Serial card. We have now changed that and it is working correctly. Thanks

OK great! Thanks for the update!