Hi All

I have a S7-1214 communicating with a air Sampler via modbus TCP ,PLC is Client

sometimes the connection locks up if the sampler is powered down and rebooted

the only way to restart comms is to change the connect Id to another number then comms restarts

does any one know why this would happen and is there any way in the software to reset the connect ID to allow restart of comms ?

regards

Mel

Hello,

maybe my idea is connection resources reservation. Try do simple disconnect from Server (use block input available for general) and you then will have free connection resources to repected connection ID. Then check if disconnection is ok and try reconnect again with same conn ID. This way I see as solution in my opinion. Other thing is if Server has some not correct functionality with Client connection and can't free own resources/connection in case of loosing connection of Client. Here I recommend use some PC app (general TCP app is enough not with MB TCP) with test connect to Server and then simulate same procedure to know what will happen. Then you can better know what steps you need to do.

Hi thanks for the reply

If I disconnect the modbus client using the Disconnect the client shows not connected but does not cure the problem when trying to connect againg

unless I enter another Connect Id it will not connect it is though the PLC is not releasing the connect ID for re-use

as this system is on a machine sampling the air then 

the system needs to reconnect the device successfully to enable sampling and logging to start  

Regards

Mel

Hello,

show us pls zipped screenshots from connect DB and also Client code in Online, this is trange. Probably your partner device can't simply resolve that problem and only after some time/power of release your Client info/connection. Make that tests with PC app as I sugested, simulate that situation. You must be sure what side does that problem.

Update: pls have you some ERROR or STATUS values indicated some problem? Pls make also conditions for that to see.

Hi 

I am not on site with this at this time the so the solution at the minute is to reboot the Plc when it happens 

as soon as i can check I will post screen shots

many thanks

Mel

I encounter a similar symptom when re-init data block on download, my solution was to use a separate tdiscon block. I also encounter that the disconnect input on mb_client didn't work.

Hi 

This looks promising will give it a go when I eventually get to site

Thanks

Mel

Thank you the solution definitely helped resolve the 16#80A3 error that kept on persisting.