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General Category => Do-more CPUs and Do-more Designer Software => Topic started by: MBAutomation on May 28, 2021, 11:37:57 PM

Title: Coms, Again
Post by: MBAutomation on May 28, 2021, 11:37:57 PM

I have a second question on more com-related issues.    I am communicating with 4 PLCs.  I currently lost coms to 2 plcs with the RX function. fault code is  2 (0x02)= Out Of Sessions: the remote PLC currently has 32 concurrent connections and cannot accept any more.   I have 4 PLCs and 1 HMI.    I have clock bits on everything.  I also have the Driver error, when I try and find it it doesn't show anything is wrong.


Any ideas on what I should do next?


Thanks

Title: Re: Coms, Again
Post by: BobO on May 29, 2021, 12:12:23 AM

Quote from: MBAutomation on May 28, 2021, 11:37:57 PM

I have a second question on more com-related issues.    I am communicating with 4 PLCs.  I currently lost coms to 2 plcs with the RX function. fault code is  2 (0x02)= Out Of Sessions: the remote PLC currently has 32 concurrent connections and cannot accept any more.   I have 4 PLCs and 1 HMI.    I have clock bits on everything.  I also have the Driver error, when I try and find it it doesn't show anything is wrong.


Any ideas on what I should do next?


Thanks

The maximum number of sessions is 32. You?ll need to use Modbus or Peerlink for anything beyond 32.

Title: Re: Coms, Again
Post by: MBAutomation on May 29, 2021, 12:31:01 AM

I'm confused about the connections.   What is considered a connection.  Is that a single device like a plc, or how many times a request is sent within a certain amount of time?

Title: Re: Coms, Again
Post by: BobO on May 29, 2021, 08:43:59 AM

Quote from: MBAutomation on May 29, 2021, 12:31:01 AM

I'm confused about the connections.   What is considered a connection.  Is that a single device like a plc, or how many times a request is sent within a certain amount of time?

Do-more's native protocol is session based. A client logs into the server and gets a session handle before it can access data. When DmD or an HMI connects, it uses and maintains a single session. If a session fails, because the client doesn't use it and didn't log out, the PLC frees it after some time, I think 30 seconds. There is a status structure for the native protocol (which I don't recall at the moment) that has a session count member, so you can track exactly how many sessions are in use.