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Can't connect via USB after setting up modem on Com1

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I have set up a Enfora modem on Com port 1 on the PLC and now I cant connect via the USB port. I get the following message:


I am using Com 2 for Modbus so can't use this for the modem. I thought that connecting to the USB port would disable Com 1 and this would be OK.

Can some please offer advice on how I can use Com 1 and USB but not at the same time. It would be OK if I could enable or disable the modem via an operand.

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  • MVP 2023

You'll have to put some code in to not init the COM port and disable other logic that references it and then cycle power if you want to use USB. The USB port is a built-in USB->serial converter using COM1. The easiest thing to do is pony up for an Ethernet port and do your programming through that.

Joe T.

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Thanks Joe, that all makes sense. I think I'll go with both options. I'll buy the Ethernet module for development purposes and have a disable button somewhere and reboot the PLC if I need local access when the project is complete.



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