I have some red lion g306A Hmis connected to a Dh485 network with 4 slc 5/03 and 1747-aic modules and I keep burning out comm ports on the screens. there are slc 500s connected 2 at a local station and the other 2 are at a remote station with areial comm line in between. the engineer that installed the screens originally recommended some phoenix contact rs485 isolation repeaters to isolate the comm line. So I installed the siemens equivalent (my wholesaler is a siemens dealer) rs 485 repeater they seemed the same except the siemens didn't have a spot for the common wire. so I ran the wire through a 24V surge protector and installed the new HMI which lasted only a day or so before the comm port was toast again. Does any one have any ideas on testing to see what is going on or ideas for products that could help me get these hmis to last.
Thanks
Thanks