M340 Connection Issue

[Andrew_W]

Good Afternoon All,


I'm trying to connect to a M340 for testing purposes, and I seem to be having a weird issue, I can connect and download the program using the USB, but after the program has been downloaded if I disconnect and try to reconnect using either the USB connection, or ethernet connection I get the error "Error during connect" when I test either connection via the Set Address box it says it can connect. Any idea on how to fix this?

 

[Corsair]

I haven't got an exact answer, especially for the usb side, and I don't have Unity on this machine.

If the selector switch is set to the 'default' or 'bootp' position you can lose comms to the Ethernet after a power cycling. Most of the time it seems that the easiest thing is to download the program (which includes configuration) over the usb. Kill the power, pull the processor, and set the switch to the 'stored config' position so the Ethernet starts up on the address that you downloaded.

For this to work on the Ethernet side you must have the Ethernet comms configured correctly. This involves going two places in the software. One place is setting up a network which includes putting in the IP. The other place is assigning that network to the CPU. If both steps are not done the Ethernet will not come up after the power cycling.

If the rack that contains the CPU has a bus extender module in the far-right slot and that bus extender is not completely cabled to another bus extended in a different rack with the proper line termination resistors I have seen where the processor refuses to wake up. Temporarily remove the bus extender from the CPU rack and see what happens.

 

[Corsair]

Also remember making sure the IP address on your computer is in the same subnet range as the PLC. In some cases I have to temporarily change the computer IP to be in the same subnet range as the PLC's MAC-derived default IP address. After the download the computer is changed back to the subnet range that you want to use. Downloading via USB simplifies this procedure as then you don't care about the default IP. That's what is perplexing about your situation - usually the USB comms stays working. There's lots of things that can cause the Ethernet to not work.