smr99 Posted June 18, 2015 Share Posted June 18, 2015 I inherited a system based on Turbo PMAC2 PCI Ultralite that has been running with little trouble for years. Unbeknownst to me, the system has the battery-backed RAM option (16B, I believe) and we use I46=1 to keep the P-variables in BBRAM. The system has been operational for well over 5 years and to my knowledge the battery has never been changed so I expect it is dead. And therefore the contents of the P-variables will be garbage at boot-up. What I'm wondering is: can this possibly cause corruption after writing good data to a P-variable? For example, suppose I say P101 = 33; is it possible that a later read from P101 will be corrupted due to the dead battery? Thanks, -Steve Link to comment Share on other sites More sharing options...
Omron Forums Support Posted June 18, 2015 Share Posted June 18, 2015 Hi, I am not completely sure, so I have been trying to find a PMAC with the BBRAM option (and no battery) to test this. In the mean time, are you able to connect to your PMAC? If so, can you try writing to a BBRAM location, and see if you can read the same information back? Below are the batterybacked memory locations: X/Y:$050000 - $053FFF Standard BBRAM Option (32k x 24 mapped as 16k x 48) X/Y:$050000 - $05FFFF Extended BBRAM Option (128k x 24 mapped as 64k x 48) L:$050000 - $051FFF Alternate location for P0 – P8191 (when I46 = 1 or 3) L:$052000 - $053FFF Alternate location for Q0 – Q8191 (when I46 = 2 or 3) You can try it with an M-Variable like M1000->X:$50000,0,24,S Then write M1000=10 and see if you can read it back. Link to comment Share on other sites More sharing options...
smr99 Posted June 19, 2015 Author Share Posted June 19, 2015 In the mean time, are you able to connect to your PMAC? If so, can you try writing to a BBRAM location, and see if you can read the same information back? Thanks, Charles. I didn't try exactly your test, but what we did is overwrite the problematic P-variables with valid data. The system began to function normally again, so I believe that reading does work. At least most of the time. What I was really trying to ask is whether we can rely on this or whether it may flake out occasionally. I am going to recommend replacing the battery to avoid future problems, but was just worried about the interim. Link to comment Share on other sites More sharing options...
smr99 Posted June 19, 2015 Author Share Posted June 19, 2015 I am going to recommend replacing the battery to avoid future problems ... On the topic of replacing the battery: I looked at the Turbo PMAC User, Hardware, and Software Reference Manuals for information on the type of battery and how to replace it. All I could find is: "The battery is located at component BT1." Are more details available somewhere? I am not physically on-site, so I can't check: If we open the computer is it easy enough to find the battery? Does the battery have sufficient markings to find its part number for replacement? Link to comment Share on other sites More sharing options...
steve.milici Posted July 1, 2015 Share Posted July 1, 2015 Yes - the battery is near the CPU section of all PMACs. Link to comment Share on other sites More sharing options...
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