750-8000 cpu is connected to 750-362 via tcp.
When the power goes off, the communication with 750-362 is broken and there is no connection. Although auto connect is turned on in my tcp settings. When Codeys goes online and acknowledge, the communication starts again. How can I overcome this problem?
Can you please confirm that you are using FW4?
I have encountered the same problem using the 750-8000 as a Modbus master device (with any Modbus slave device). This continues to be an issue with FW04. Looking at Wireshark, the BC100 will send a single SYN telegram and will āhangā in a busy state until this is acknowledged. This causes an issue when the Modbus slave goes offline as the telegram is never acknowledged.
Currently, the only work around I have found is to restart the BC100 or disable the Modbus auto-reconnect and ping the target slave device until it is back online. Once the ping request is returned consistently for a few seconds, then reset the Modbus communication.
I am using this exact setup on a recent project and not encountering this issue with FW4. Make sure that you create a boot application so that a copy is burned and not lost on power down.
Also make sure the tiny internal switch inside the controllerās hatch is set to āRUNā (all the way up). For the Ethernet device, make sure you select the ethernet interface of the control (typically eth0) and I also scheduled my device on the Main Task. Iām not using a gateway and the subnet mask is the typical 255.255.255.0. On Modbus TCP Master I have Auto-Reconnect checked. Timeouts on the master and slave are 1000 ms (you could fiddle with this and increase the timeout too). One thing I screwed up was the IP Addressās last octet was 0 and that wont let the Modbus TCP talk. I set my controller to 192.168.1.1 and the 362 to 192.168.1.2 which fixed my issue. But for my particular problem, I wasnāt getting any connection at all. You can check to see if its your master device or slave device by running a modbus program (like Qmodmaster) and seeing if you can still connect to the slave right away. If you can, then its your modbus master for sure. QModMaster download | SourceForge.net And then if itās your master, you can narrow it down to settings or controller issues.
Working with the support team, we have confirmed that issue WAT36345 (listed as [fixed] in the FW04 release notes) is still occurring. Hopefully we will have a resolution to this soon.
Iāve also noticed this. For my case if was when powering up a VFD and the PLC simultaneously, the PLC booted faster than the VFD resulting in the PLC not getting any communication with the VFD. Rebooting the PLC after the VFD has booted fixed communication ā¦