Difference between data provided to OPCHDAClient by 800xaHistory OPCHDA server and BasicHistory OPCHDAServer
Hello,
System:800xA 6.0.3.2, No rolls ups installed for History server
I am working on developing Hourly,Monthly and yearly energy consumption reports using data direct.Initially data logging was done via Basic History alone.Currently we have added an 800xa History server to the system.
I have now also created an 800xA History log(10sec sampling period) for the same tag being logged by a Basic History log (10sec sampling period).
For reporting requirements, I have to calculate Hourly energy consumption.
From the options available in data direct, I found that fetching 25 samples for a 25 hour period using aggregate 'MAX/MAXACTUALTIME' (Range/Delta aggregates also experimented with) meets my requirements. However, upon comparing the data fetched when Basic History log is selected and when 800xA History log is selected, I observed that 800xA History server tends to apply aggregate only up to the 53rd minute of each hour. As a result my energy calculations are incorrect since the values from 53rd to 60th minutes are not used for applying MAX aggregate.
The data fetched from Basic History log is correct.
To cross verify this I performed above procedure via Matrikon OPCHDA client and made the same observations.
It would be great if somebody can explain why there is such a difference between the two Historians.A solution to resolve this would be helpful.
PFA screenshots of OPCHDA Test client.
Regards
Rahil
System:800xA 6.0.3.2, No rolls ups installed for History server
I am working on developing Hourly,Monthly and yearly energy consumption reports using data direct.Initially data logging was done via Basic History alone.Currently we have added an 800xa History server to the system.
I have now also created an 800xA History log(10sec sampling period) for the same tag being logged by a Basic History log (10sec sampling period).
For reporting requirements, I have to calculate Hourly energy consumption.
From the options available in data direct, I found that fetching 25 samples for a 25 hour period using aggregate 'MAX/MAXACTUALTIME' (Range/Delta aggregates also experimented with) meets my requirements. However, upon comparing the data fetched when Basic History log is selected and when 800xA History log is selected, I observed that 800xA History server tends to apply aggregate only up to the 53rd minute of each hour. As a result my energy calculations are incorrect since the values from 53rd to 60th minutes are not used for applying MAX aggregate.
The data fetched from Basic History log is correct.
To cross verify this I performed above procedure via Matrikon OPCHDA client and made the same observations.
It would be great if somebody can explain why there is such a difference between the two Historians.A solution to resolve this would be helpful.
PFA screenshots of OPCHDA Test client.
Regards
Rahil
Asked 2 months ago
Voted best answer
1
As per my understanding from your description, it could be related to the difference in sampling time of the values between Basic History and 800xa History. I would suggest you to compare the raw values between the two historians and that will give you a fair idea where the problem could be.
Also the other point could be the compression factor which has been enabled in the 800xA log configuration aspect. Try after disabling the compression.
Also the other point could be the compression factor which has been enabled in the 800xA log configuration aspect. Try after disabling the compression.
Answered 2 months ago
Answers
0
Hello Mr. Sethu,
Thank you for the suggestion.The issue was with compression being enabled at 0.001.
Please find below the screen shots of logged data via Log Status tab before and after disabling compression.It is clearly seen that the data was earlier logged at 10 minute intervals instead of 10 seconds.Post disabling, data is being logged at 10sec intervals.
With Compression
Thank you for the suggestion.The issue was with compression being enabled at 0.001.
Please find below the screen shots of logged data via Log Status tab before and after disabling compression.It is clearly seen that the data was earlier logged at 10 minute intervals instead of 10 seconds.Post disabling, data is being logged at 10sec intervals.
With Compression
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