Two AB 505 Questions: PUMP ALTERNATOR and N7:6 retentive

1. Does anyone knows of a good PUMP ALTERNATOR logic for AB 505 that will take into considerations Pumps that are Offline because of maintenance reasons?

2. How can I make the value inside N7:6 retentive when Electricity goes out and a New logic is downloaded to the PLC?


Thanks


Andy

I'm not sure about your question #2... I've never used 5/05s but in 5/03 and 5/04 processors the integers are retentive during a power loss. Are you writing to this integer from something else (maybe an HMI or PC based interface) that cycled power at the same time? I never lose my integer values during a power cycle.

Question #1 is gonna require more input. How many pumps are you running and do they have HOA switches? I can assure you the answers are on this forum

I'm just guessing here but it sound's like Andy's CPU has the logic stored in an EEPROM with a 'load from eeprom always' condition set. This may overwrite everything on a power cycle. This doesn't solve anything but it's a guess as to the problem. Andy, please help us here.

I think Andy stated the problem....

2. How can I make the value inside N7:6 retentive when Electricity goes out and a New logic is downloaded to the PLC?

Click to expand...

The only time NEW logic is downloaded to the PLC is if he does it himself or if.....

I'm just guessing here but it sound's like Andy's CPU has the logic stored in an EEPROM with a 'load from eeprom always' condition set.

Click to expand...

As far as I know there is no way to update stored EEprom values without a developement software program to initiate it.

One suggestion is to use the "NEW" value as the burn value (this would get you up to date as to the last burn) then use an error recovery routine to prompt the operator that there has been a power failure and the old value will be used, then the operator is aware of the problem and can take the proper steps to reset the value to current settings.

Now to question 1, the way we have done it is to use an input from each pump MCC HOA switch, if the HOA switch is not in the "Auto" position the pump is NOT available.

I agree Bernie, SLCs don't just lose integer values. Andy didn't mention EEPROM so I didn't specify, but it could fall into the "something else" category. We don't ever start up from EEPROM for this very reason. Bitmore, that's why I was confused about the question, I assumed (hoped) he knew that values could be written over during downloads.
I track highest production hours and days and I also track the previous 20 days of production. It would be unfortunate if power losses erased this data.
Just as a side note, for anyone who has operators that leave a conveyor line running when they go home, I use a time based bit to turn the line off for one second at midnight (the lines usually shut down at 11PM). I have lines that go to sleep when a certain period of inactivity occurs but the lines all go off at midnight.

Rube we posted close to the same time!

Maybe we fit that "sharp minds..." theory. You also beat me to the specifics of the HOA switche position being permission to involve a pump. I used to work in a water bottling plant that had NO insulation around any outside piping (thus quoth the Engineer, " it freezes in Texas Nevermore). I came up with a solution after the plant was down THREE DAYS with ice in the lines. We used our transfer pumps to cycle water through lines from the silos, into the building, and right back into the silos. Moving water don't freeze, and I ain't lagging or heat-taping them pipes. We did not move water by using a pump that had the HOA switch in the H or O position.

By the way, we never froze pipes again while I worked there.