800xA 5.0 IM logs
My customer has a 800xA 5.0 system with an IM server and Advant 450 Controllers. Data is used for enviromental reports.
I have 2 problems in this system:
1. most log configurations logs from TTD-logs in the controller. Sometimes a log stops loggin values. The reason seems to be that the TTD logs stops providing data, since the problem can be cured by restarting the controller. However on a power plant this is not possible most of the time, so I'm looking for a way to make the TTD logs run again. I have tried to kill and restart the DCTA100 task in the controller, but that didn't help. I have been told that DCTA200 and DCTA500 are restarted automatically when you restart DCTA100, so I have not tried to restart those manually.
2. some logs suddenly start to log values on the wrong time - e.g. a 1 hour log logs values at xx:22:00 in stead off xx:00:00. I have tried to stop/start the log. How do I make these log at the correct time again.
Thanks in advance.
AFAIK the DCTA200 and DCTA500 tasks are NOT restarted automatically when you kill. / start DCTA100. The procedure I have used is allways to restart all three tasks, because you do not know which task actually died.
Anyway, as you know those tasks die when the AC450 controller load gets too high. So the root cause is probably your AC450 controller load.
If the load is very heavy, then yes, logging can be delayed. Check the settings on the TTD database element and you will see there is a setting for maximum delay expressed in percent. The default value for this IIRC is 50%, so a 1 hour log could be up to 30 mins late if your controller is overloaded.
Try to find why your AC450 load is so high by doing a detailed task load analysis using the ANPER command. Check if the load is coming from the PC program interpreters or from some other source like subscriptions to the controller from operator stations etc.
You should also consider using 800xA logs instead of TTD logs
Local vs system time problem?
All values are stored in UTC.
A log storing at midnight Stockholm-time is in reality storing on UTC+1 or UTC+2 (when on Daylight Savings Time).
Asking for data will add local time offset (+1 or +2 hours) and will cause answers to look different before, after and across DST shifts.