We use the ModbusTCP client in the RUT241 to retrieve data from a PLC.
We use several clients on the same IP, as data from other controllers is stored there, whose data is to be written to separate devices in the cloud platform Thingsboard using data senders.
To do this, one data sender retrieves the data from the corresponding Modbus client and then writes the data to the device via MQTT.
We have been doing this since firmware 7.8.2 and since 7.12 it no longer works. Not even with the latest firmware.
The last firmware with which this works is 7.11.3.
The behavior is:
the first activated Modbus client in the list receives data, the next one does not. A total of 11 clients are required. Even if only 2 are switched on, it does not work.
We have tried various settings such as time outs, delay etc.
With “always reconnect” on, not a single client works.
Do you have a solution for this so that we can also use higher firmware versions?
Apologies for the delay. Could you please confirm whether the issue you’ve described is still present on firmware version 7.13.4?
Also, as I understand your setup, you’re using the Modbus TCP Client to retrieve data from a single IP address (your PLC) and then sending this data via MQTT to the ThingsBoard platform. Could you clarify why it isn’t possible to configure a single Modbus TCP device (server) in the Modbus TCP Client settings and manage the addressing through the various Modbus requests instead of running multiple Modbus TCP client instances for the same IP?
As your configuration sounds a bit unclear and specific, would it be possible for you to share some screenshots of your Modbus TCP Client configurations and any additional details or clarifications?
We have only 1 Modbus Master in the main PLC.
All other PLCs do not communicate by ModbusTCP but ProfiNet.
We don´t use several Modbus Masters because that would consume too much RAM in the PLC.
So one Master, one Data Block.
In this Data Block is all the data from all PLCs.
But we need one device for every PLC in the cloud.
So me made 11 Modbus Clients so we can make 11 data senders.
Each data sender can send the data from one PLC to one device in the cloud.
Otherwise it would be too much work to separate the data in the cloud.
I tried to upload a zip with the modbus_client file, but I am not allowed to do so by your system.
Apologies for the delay in getting back to you. I just wanted to follow up and ask whether the initial issue with sending Modbus data via MQTT has been resolved. If not, could you let me know if the issue still persists when running on the latest 7.15 firmware release?
Also, if I understood your setup correctly, you have 11 Modbus TCP clients configured with the same IP (the main PLC), each acting as a data sender for a different PLC’s data block. Out of curiosity, is there a particular reason why you can’t configure a single Modbus client instance with multiple requests (each targeting the different register ranges for each PLC’s data within the central data block on the main PLC)?
We tried it with 7.14, but not with 7.15.
We will do this and report back.
The PLC data block is always the same, just different bytes are addressed.
The reason is that we need different data senders to address different devices in Thingsboard. If every data sender would use the same modbus client, they would all have the same data in the message.
