Question

Hi!

I've tested successfully several of the TRB255 features; thanks a lot for your work.

My question is related to the Modbus gateway feature. I have 2 Modbus devices connected to this RS485 bus, with different Slave Id and I can read data from both of them using 2 Modbus TCP clients, but they can't be connected at the same time. When I connect to the slave with Id=1, the client connected to the slave with Id=2 is disconnected and viceversa. I would like to keep the TCP connection alive all the time.

Is there any solution with the firmware version it has (TRB2_R_00.02.06.1) or any newer update?

Thanks in advance!

Answer 1

Hi,

Do you mean that you've connected two devices through one RS485 port and communicating with them through Modbus TCP? And once you've connected to one device, the other one is not reachable?

EB.

Comments

Hi Ernestas,

I can connect to both devices (or to more devices if I connect them to the same serial bus) through TCP using the Modbus gateway function of the TRB255, but not simultaneously. That is, when I connect to any of them, the one connected in that moment is automatically disconnected (socket TCP). Of course, every device connected to the 485 has a different "server address" and I've checked that I'm connected to the expected device every time.

Thanks in advance.

Answer 2

Hi Ernestas,

I can connect to both devices (or to more devices if I connect them to the same serial bus) through TCP using the Modbus gateway function of the TRB255, but not simultaneously. That is, when I connect to any of them, the one connected in that moment is automatically disconnected (socket TCP). Of course, every device connected to the 485 has a different "server address" and I've checked that I'm connected to the expected device every time.

Thanks in advance.

Answer 3

Hi,

I've installed newest firmware version (TRB2_R_00.07.00) but it's still happening.

Will this issue be fixed on forthcoming updates?

Comments

Did you find a fix for this? I’ve got a similar issue with 2x clients over RS485 and I’m forwarding data to an MQTT broker(RTU to TCP). If I set the poll rate to the same value (60s) for the clients I get mixed data, so I’ve had to “step” the poll rate to get it to work (Client 1 60s, client 2 59s).

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No, I'm sorry. I haven't had an answer or fix yet. I suppose your 2 Modbus clients can't keep the connection opened at the same time  either and they have to be reopened before any MQTT data is sent. I don't know if the Teltonika team is aware of this and If it is gonna be fixed on forthcoming firmware updates.

Regards.