Posted 11 Jan 2023 (edited) Hi all, I'm new to Allen Bradley but have some experience with TIA/STEP 7 - not that it relates to this issue! We have 2 side by side systems but running a SLC 5/05 CPU, with the same program but different IP addresses, connected via a network switch. All has been fine until both were power cycled - system 1 CPU program has dropped but not system 2? The IP address for system 1 has been reset and can't be pinged from either the switch (but 2 can) or directly connected to the PLC port. Steps I have carried out as below, so would appreciate anyone skimming over and pointing out where I've gone wrong/something else to try; - Used BOOT P DHCP tool directly connected to system 1 plc, add relation assign original IP address, click Disable BOOT P. - Attempt to ping (after changing laptop IP to same loop but different node) = no connection - same cable used to connect to switch and ping system 2 which worked so cable and adaptor settings good. -not going to help with the immediate problem but battery swapped out for new on CPU. Any assistance and advice appreciated! Edited 11 Jan 2023 by CraigROCK Massive spaces inserted into opening post unnecessarily Share this post Link to post Share on other sites
Posted 11 Jan 2023 Sounds like a dead battery. Those old processors use a lithium battery to hold the program between power cycles. When bad, there's a red indicator light right on the front panel. There's also a status bit in the processor's status file. You will need to reconfigure and restore the PLC as if you were commissioning a brand new one. Rockwell's BOOTP/DHCP tool is the typical way to re-establish its IP address. You must wait until the PLC accepts the address before you disable BOOTP.. Consider doing the BOOTP while on the same switch with everything else. 2 people like this Share this post Link to post Share on other sites
Posted 11 Jan 2023 47 minutes ago, pturmel said: Sounds like a dead battery. Those old processors use a lithium battery to hold the program between power cycles. When bad, there's a red indicator light right on the front panel. There's also a status bit in the processor's status file. You will need to reconfigure and restore the PLC as if you were commissioning a brand new one. Rockwell's BOOTP/DHCP tool is the typical way to re-establish its IP address. You must wait until the PLC accepts the address before you disable BOOTP.. Consider doing the BOOTP while on the same switch with everything else. Hi pturmel, Thanks for the reply. I did suspect that was the root cause of the issue, swapped it and then the site had another power surge over the weekend knocking the system out again. Come in on monday and the program has been dropped again (no EPROM fitted to CPU from what I can see)! This time, the BOOT DHCP tool doesn't seem to be writing the IP address to the CPU as I cant ping it! Going through RSLinx it also cant see it, when i configure the driver for IP, using the IP address assigned. This is actually the first time I've come to use AB PLC's so I'm rapidly running out of things to try - searches on these forums have been a big help in getting me to the above point, along with what ive picked up from Siemens! My next steps I think will be to replace the CPU (if held onsite) unless anyone has any further advice/tips? Share this post Link to post Share on other sites
Posted 11 Jan 2023 If it won't take an IP address at all, then I would think the processor is toast. Your next attempt would be to use the serial port to get in, and manually configure channel 1 that way. 1 person likes this Share this post Link to post Share on other sites
Posted 11 Jan 2023 Consider buying some UPSs for your controls, at least to absorb surges. Cheap ones, even. 1 person likes this Share this post Link to post Share on other sites
Posted 11 Jan 2023 Hi pturmel, Glad to see my train of thought was along the same lines as an expert in the field! I have installed a new CPU and sailed through the process to reinstall. System now back up and running! Thanks again for the quick reply and i will be using this as an example to strengthen my existing argument to get all PLC's UPS protected! Regards, Craig Share this post Link to post Share on other sites
Posted 13 Jan 2023 Before you trash the bad CPU or ship it to a Radwell or Rockwell for refurbish credit can I recommend you try a reset to factory conditions on the CPU. https://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/54328/loc/en_US#__highlight Share this post Link to post Share on other sites
