Ge Fanuc PLC series 90 / 30 331 CPU

Hi guys.

Im a total PLC noob.

i suspect a dead 331 cpu. Unable to communicate with it using the LM90 start utility. But i could on another CPU so lead, comms and software ok on laptop.

Within the 331 CPU there are two sockets for chips.

One with CP3A3 written under it and another with the jumper selection under it.

My question is what is stored on the chip in the socket with CP3A3 under it. The chip itself has 395-045D (or o) 8.21 written on it. I think it may be CPU firmware upgrade but i am hoping it is an eeprom with the program on it.

I do have a copy of the program and a lead but the old laptop we had LM90 on is long dead.

Thanks for your time!

WOW!!! Talk about diving into the deep end to learn how to swim. For being new to PLC's you sure got handed a... lets call it "fun" challenge. It's been a lot of years since I played with (beat my head against the wall really) 9030's but...
To start off with, if you're thinking about pulling the chip with the program on it from one processor and putting it in another, without any programming software (I'm not sure what "LM90 start utility" is but I'm guessing it's not the full software package), I wouldn't. The likelihood of it working is remote at best (to many variables) and you run the risk of having two processors that are now bricks. Are you accessing the processor via the programming port with a Horner converter on it? If so, and that's working on another processor, then your assessment of a bad CPU is likely correct I.E. (if memory servers me) that port only serves one purpose so its not likely that its configured wrong. Having said that if you have access to a handheld programmer then you should be able to connect (if it's a good CPU) and check the configuration of the port. I believe your best bet is to find a copy of LM90 or upgrade to Unity Pro and program the working CPU from scratch. Having said that, if this is a learning project or something other than a required fix, I'd pick an Allen Bradley MicroLogix 1100 or a Micro800. They both have free versions of programming software and are (in my humble opinion) much easier to work with and program (and find accessories for, and find people who know how to program them, ect...).
Good luck and keep us posted on your progress.

I'm not quite sure what the lm90 start utility is or if you are referring to the LM90 Package. Either way Myself I would contact your GE Supplier and you may obtain a copy of Proficy Machine Edition you have a trial period it will make things a bit more simplified.. I am assuming you are using the Programming port on the 9030 power supply for coms.. Are you using the same power supply and a different CPU and able to obtain coms I would say yes faulty CPU. The chip you are referring to is the Firmware chip and the program is not stored on this chip but I have seen cant remember if it was the 313 or 331 that if you swap power supply quickly it will retain program for a minute. any longer than that all is gone the 331 does not have flash memory so once power is gone and battery is drained you will lose program. the 8.21 is the firmware revision and I believe 8.40 was the last for the 331. I would verify using the same power supply and different cpu you can indeed get coms not sure if you are using a complete different systems for coms or not.. hopefully you have a backup after power is lost and no battery all will be gone.. lights on the powersupply will say something also pwr ok should be lit.. if ok not lit probable due to hardware issue..

As sjohnson has stated, the labeled chip is the CPU firmware. The other socket is for an EEPROM chip for the program memory. If there is a chip in that socket you may have a backup copy.
The sockets on my CPU331 are labeled on the circuit board as U19 (the firmware chip) and U18 ( empty in my case).
The battery to maintain RAM memory in the 90-30 is located on the power supply module. Once you have removed the CPU module from the baseplate and lost the connection to the battery the RAM memory is maintained by a capacitor (C45 on the daughter board) which will only maintain the RAM for 30 minutes or so. There is a place where you can connect a battery (labeled PL1) while the module is out of the baseplate.
What is the status of the LEDs on the power supply module when you apply power with the CPU module in place?

Thanks for replying guys!

I am only self teaching its not the end of the world if it all goes wrong. Found LM9030 software and am muddling my way through it. Its like stepping back in time!

Cheers!