slc500 fixed unit

Hi I have a slc500 1747-l30a fixed unit,right below the memory
module is another chip thats marked slc500 fx1cpu.What is this chip for? I have several other slc 500 fixed units that do not have this chip installed and they work fine. I also have a problem with 1747-l30c unit,when i try to load processor memory to eprom i lose comunication with processor.Thank you in advance to anyone who can help me with these problems

The EPROM may have a program on it that has different communication settings than what you are currently using in RSLinx. Try going into configure for the driver you are using in RSLinx and autoconfigure. This should go through all the possible communication settings for that driver and find ones that match what are on the eprom.

Once you communicate with the processor make sure if you download a new program you copy to the eprom otherwise your program will get overwritten by what is on the eprom on the next power cycle.