SLC Date & Time

Steve Meisel

Member
Join Date
Jun 2002
Location
NC
Posts
77
We have a SLC 5/04 that looses it's program on power up 3-4 times per year. We have had a lot of people look at it (AB Reps, the machine builder, etc.) and tried countless things. The only thing that seemed to help was to place an isolation transformer on the incoming power line.

My problem is when the program is loaded back into the processor the date and time is never correct. We are laser etching a part with the julian date so the date in the processor is kinda important.

Last week I changed it the machine to have the panelview write it's date and time to the processor each minute. I figured that: 1. We never have any problems with the panelview so it should retain it's data fine. 2. In chase who-ever had download the program to the processor, if they forget to set the date and time, the panelview will take if it for them.

The morning the date was off!🔨

Any ideas? I know that fixing the original problem would be the best but, I have spent endless hours on it and for now I would just like to find a solution to the date problem.
 
Hi,

Do you have another machine using similar CPU, doing a swop might be able to determine is it machine related or CPU hardware related.

Another thing I can think of would be the backup battery connector, any chance of loose/dirty pins.

Another option is to add a EEPROM and set it to load the program upon error or every power up etc. I guess you have sorted to update the system time yourself.

Good Luck
_________
 
If your Panelview is writing the date to the internal PLC clock every minute, then your date should only be wrong for 1 minute, maximum. You should double-check your date-writing routine. It may not be working correctly, or it may be writing to the wrong location. To make sure your date is totally correct, you would have to write the Hours, Minutes, and Seconds also.

Year= S:37
Month= S:38
Day = S:39
Hours = S:40
Minutes = S:41
Seconds = S:42
 
Last edited:
On our system, we have a computer (running SQL and ifix) collecting data. This computer is the clock master and sends the time and date at 2:00 am. There is no reason that it couldn't send the data more often, though. You could even use the first pass bit in the slc to request the date and time when it is powered up.
 
I feel your pain, nobody notices a mark is off on time or date in my plant until the customer calls us.

I would run the panelview and slc clocks independant, then simply generate a fault if they do not jibe (compare). That way both have to be off by the exact same amount in order for the system to operate incorrectly. Not a likely event unless you load both from a laptop that has the wrong time set in it. In which case you are simply doomed and will have to check your laptop time periodicly or log on to your network once in a while.

I would suspect noise on the proccessor if it keeps gaffing at power up. Espeacially since the isolation transformer seemed to help. You might even try a line conditioner/surge suppressor, they sell them for your computer at home pretty cheap (just wire the slc to a plug and the conditioner to your panel), just make sure your ground is good and there are no ground loops. If it fixes then get a silly scope and find your noise.
 
Bond the PLC chassis to a reliabe ground, don't rely on the backpan.


(PS, last time I told someone that they blew me off and lived with the same problem for another two years. Then when I visited the plant I bonded the chassis myself. That was seven years ago and the program hasn't been lost since.)
 
Last edited:
I had a similiar memory loss problem with a
customer in South Carolina. It seems the
building was improperly grounded and occured
the most druing severe thunderstorms.
 

Similar Topics

I was online a SLC5/04 yesterday and one thing I did was go to processor properties and set the date and time to get the PLC clock current. It...
Replies
4
Views
703
Hello everyone I have a couple questions here about our AB SLC 5/03 for our waste treatment system. The date and time on our HMI is off and I've...
Replies
20
Views
6,926
Hi, I have just flashed an SLC5/05 Cat No. 1747-L551 FRN8 with the latest available firmware from Rockwell using ControlFlash and now the CPU is...
Replies
4
Views
1,705
Hi, all We have several machines using SLC, and we find the spare parts are more and more difficult to buy. But my boss refused to upgrade the...
Replies
11
Views
3,918
Hello all, What is the best to sync time and date between Cimplicity and SLC 5/05. There is an option to run a script in the background to...
Replies
0
Views
2,442
Back
Top Bottom