GE 90-30 CPU - internal capacitors?

[becs]

I've been having a problem with the GE CPU-372 losing it's brain during a power loss. I'm not sure the age of the PLC, but judging from the age of the rest of the machine it's fairly old. I decided to change out the power supply. During the change out the power was down to the PLC for at least a half hour. Because of this I was very surprised to go back online to the PLC upon power up and find my program intact. The only explaination I can think for this is that the CPU has some internal capcitance that held for the 5 min it took me to swap the power supply and backup battery. Does anyone know if this is the case?

[RussB]

That and most of the GEIP CPUs have a fair amount of capacitance, but I have never looked at that one in detail. Also it has built in Flash Memory and in most cases it will be configured to Read the Logic and Configuration from Flash on power-up, so a battery is not needed for that. As an option Register data can be saved and loaded from Flash also. With the newest versions you can even use a Service Request to have Logic update some of those Registers. See Proficy ME online Help and the Manual for details. DO696: Series 90-30 Installation and Hardware Manual, GFK-0356 It is the same as the CPU374 with less memory. If the working program is being wiped on a power cycle, you likely have a grounding deficiency and/or the inductive loads need suppressors.