Hi i had a problem with my vlan the other day. Could nort see several of my clients and plcs. I eventually got to the root of the problem by following net work cables fro the plc to the switch, fiber to the switch in the sever room. No comms light so though i was cleaver switched from one port to another. My plcs worked but the other associated printers and clients strted behaving funny. at 1 am in the morning there was not an it person at hand to do the configerations.rt was done for 8 hours. I could have done something. What adminitration courses to you recommend for a ocntrol engingineer. Thanks