Data Logging Issue in Siemen WinCC RT Professional

[Aleem128]

Hi, I am logging tags every 24Hr in table view in siemens WinCC RT Professional. Every day at 7:00:03 AM a value is logged. WinCC takes value from PLC Program in S7-1200. Issue is WinCC is logging the previous day value in todays date. Like date is 25/10/2022 but the value is of yesterday. In program the updated value is seen but wincc log it at next day at 7 am. I checked PLC clock and Wincc clock both are having same time and date.
Below images are attached the value is shown in program but not logged in wincc. It will come tomorrow but with tomorrow date but in actual it is value of 26/10/2022.

 

[drbitboy]

Hi, I am logging tags every 24Hr in table view in siemens WinCC RT Professional. Every day at 7:00:03 AM a value is logged. WinCC takes value from PLC Program in S7-1200. Issue is WinCC is logging the previous day value in todays date. Like date is 25/10/2022 but the value is of yesterday. In program the updated value is seen but wincc log it at next day at 7 am. I checked PLC clock and Wincc clock both are having same time and date.
Below images are attached the value is shown in program but not logged in wincc. It will come tomorrow but with tomorrow date but in actual it is value of 26/10/2022.

So the problem is that, at 07:00:03 today, the data are logged with a timestamp of today's date, and what you are implicitly asking is how to make those data be logged with a timestamp of yesterday's date?

 

[Aleem128]

The value came in program logic at 7 am in morning. As seen in Tag. And Wincc Logging time is at 7:00:03 at 3 sec. So technically Wincc should log the value currently present in tag at 7 am , 3rd sec. But it takes yesterday value. Today in morning it is 26/10/2022 and wincc is showing zero. (which is previous day value). Now tomorrow at 27/10/2022. This value will be shown in logging table. But it is technically previous day value.

 

[JesperMP]

I think that maybe the logging trigger is the issue.
Does the logging trigger on scheduler, on value change, or on an external trigger ?

 

[Aleem128]

Its on logging cycle. Every day at 7:00:03 AM. The values are synchronized with PLC Program accordingly.

 

[JesperMP]

How does the associated tags update ? On use, or cyclic, or ?

 

[Aleem128]

Every day at 7 Am a new value moves in memory register. that comes from PLC calculations which is reading data from Energy Analyzer via MODBUS.

 

[drbitboy]

Every day at 7 Am a new value moves in memory register. that comes from PLC calculations which is reading data from Energy Analyzer via MODBUS.

How did a 0 end up in that register, to get logged and timestamped by WinCC?

 

[Aleem128]

I think this will clear the situation see picture in attachment. The value which was present in program yesterday is logged today. That value came in program at 7 a.m and should be logged at 3rd sec past 7 a.m. That value came in program on 26/10/2022 but logged on 27/10/2022.

 

[drbitboy]

All three of these statements cannot be true:

• The values 641611, 777252, ..., 3390598 were all calculated and written to some PLC registers by 10/25/2022 07:00:00 am on the PLC clock
• The values 0, 0, 0, ..., 0 were all read from those same PLC registers by WinCC at 10/25/2022 07:00:03 am on the WinCC clock, and then logged and timestamped.
• The clocks on the PLC and on the WinCC system are the same.

The PLC and HMI care not a whit what we want them to do, but they will mercilessly and inexorably do exactly what we tell them to do.

 

[Aleem128]

Yes the clock on the WinCC and PLC is same. I read system time. Both are same. I observed the register which I want to log at 7 a.m. The new value moved in register at 7 a.m. So I kept the logging time at 3rd sec. Despite the new value in register (the previous value replaced by new) wincc logged the previous value. But if the logging cycle is only a time stamp in wincc and not getting the actual values present in PLC at that specific time absolutely makes no sense and need further explanation.

Once the value moves in register which i want to log it remains there for 24 HR. and not replaced by zero. But wincc log previous day value.

 

[JesperMP]

Let me rephrase the question.


How does WinCC update the associated tags ? On use, or cyclic, or ?

 

[Aleem128]

Cyclic 1 day. Every day at 7 am 5 sec.

 

[JesperMP]

Base on what you have written.
You are logging at 7:00:03
And the tag is updated at 7:00:05
Then it is logical that the logging uses the old value.

Try this.
Update the tag cyclically, for example with an tag update cycle of 60 seconds or like that.
Then log the value with an "on change" trigger.

 

[Aleem128]

Sorry its on 3 sec. But value moves in register on 7:00:00 . either Logging is on 03 or 05. new value should come, because new value was updated in plc program before logging. Logging on change is a solution which i think will work as advised by you.