Thanks Chapssa - the guys got all the units up and running by increasing the UPS voltage from the information given to me by Driverocks and they are now going through a rotation back to GE for servicing. The other rig replaced them all so they don't have a problem.
Funny thing is GE don't...
MPI is multi-point-interface and is based on RS485 therefore you do not need two ports as all other ports are connected together by two cables with terminating resistors at each end.
Your HMI and PC would have to have ports capable of connecting to the network. You can get (or used to be able to...
UK sector North Sea and Caspian Sea. Maybe down Brazil sometime next year but will mostly be on a shipyard job here. Would be glad to meet up sometime and again thanks for your help - I've passed on your information to the rig chief electrician and I did not take all the crerdit!
Drivesrock
Yes they were both 24VDC supplies and they are operating exactly as you describe. Both systems failed after putting the 24VDC UPS power supplies off for installtion of new generator control gear. The rigs had them powered up almost constantly for years because even after blackouts...
Hope someone can help - I have recently been on a couple of offshore drilling units that were fitted with GE Multilin 489 generator protection relays. The units are about ten years old (old version). They previously worked for around 9 years on one rig and 3 years on the other (but rig...