Got a customer who has an existing MD plus system with the following physical configuration. A four wide carrier contains a redundant controller/power supply pair. This is attached to vertical carriers 1-3, with a 1 meter long "bottom cable extender" connecting to vertical carriers 4-6. They want to add two more carriers, and have designed the addition like the diagram in the article "Calculating the Total Length of a Legacy Vertical System" in DeltaV Books Online. This means there should be a 2 meter "top cable extender"connecting from between carriers 5 and 6, and carriers 7 and 8 (the new ones).
However, we have what we think is a bad top cable extender that caused the controllers to reset when we tried to plug it in, multiple times. The 2 meter top cable extenders have a one week ship time from out of the country, so we were trying to find a suitable replacement. We decided to try using a 1 meter long "bottom cable extender" on the top and see what happens.
When we originally connected everything up, there was power going to the new IO, but when I tried to scan it in DeltaV Explorer, it didn't find any of the new cards. Our first thought was that the 24V injected field power needed to be tied into them for DeltaV to recognize them. Does anyone know if this is the case? I thought they were on different buses, so it seems unlikely.
I also found some relevant calls leading me to believe that the top and bottom cable extenders are not interchangable, but I can't figure out why. The only relevant difference seems to be the length. Is this what is causing our problem? Anyone know what the difference is?
The system is on DeltaV 11.3.1... guess that's important.
Thanks in advance for any help you can offer.