![]() ![]() If this is Modbus RTU then when someone un-wired the VFD to remove it from the site they probably broke the Modbus RTU circuit.Īs long as the circuit is not broken removing a Modbus Rtu device will not cause the whole modbus to stop working. Therefore, if they locked out the drive because the pump is out for service, would that affect the Modbus communication? If So, then we Since the Modbus has always been working properly, to my knowledge, even while the pump was out for service. and might of forgot to put the drive back in the modbus loop? The only thing that comes to mind is that, someone removed the drive from the modbus loop while the pump was sent out for service. But it's weird that it won't communicate anymore. I'm trying troubleshoot this remotely with the customer. Here's the story, since the pump came back from service it won't communicate the PLC anymore? We checked all the communication settings like baudrate, polarity.ect If the VFD is powered down would that affect the entire modbus communications line? One of them was locked out, since a pump had to be sent out for service. Setting the Login key to false will allow this device to connect successfully.I have a question about modbus communication, we have a PLC controlling two VFD's. If they dont log in then you will see the following in the Modbus Server log… Not very many MODBUS clients implement a login. If any configuration needs to be changed it will probably be the Login setting. If a request is not made within this amount of time then the JNIOR will close the connection. The Timeout setting is the number of milliseconds to wait for a MODBUS client to poll the server. Most likely this will NOT need to be changed. Lastly, you can change a few configuration parameters for the MODBUS server under the registry tab. To verify that the MODBUS server is running we can list the listening network sockets using the netstat command. You will need to reboot the JNIOR at this point to get the MODBUS Server to start. This will tell the JNIOR to run the application when the JNIOR boots up. You will see a list of applications that are loaded on the JNIOR. Half way down the left side click on Applications. To activate it go to the DCP, click on the Configuration tab. It must be activated by the end user before the the MODBUS connection can be successful. It does not run by default when the JNIOR is shipped. The MODBUS server running on the JNIOR is a separate application from the Operating System. MODBUS client is not able to connect to the JNIOR
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