Unsolicited configurations for Present value problem

[maherhodali]

Hello all

I am facing problem in receiving values from field device tag throw BACnet protocol

-receiving mode for the present value configured as unsolicited "Change Of Value", archiving configuration "Old/New Comparison " also inserted to the present value
to archive all value received from the source.

-Unsolicited configurations depends on the change of the present value, once the changing of the present value exceeds the COV increment, the field device send the value to WinCC.

in my case present value representing percentage of opening valve, no smoothing inserted to the present value and COV_Increment Value is 1

the result of archived values as following:

AHU-C-TR-09 - 2-WayCoolingValveFeedback 3.590329409 2020.01.16 12:15:41.359
AHU-C-TR-09 - 2-WayCoolingValveFeedback 2.506200314 2020.01.16 12:15:43.987
AHU-C-TR-09 - 2-WayCoolingValveFeedback 1.421855211 2020.01.16 12:15:47.300
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0.394196868 2020.01.16 12:15:53.343
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0.276706159 2020.01.16 12:15:53.755
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0.227470338 2020.01.16 12:15:54.123
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0.181976274 2020.01.16 12:15:54.455
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0.151686445 2020.01.16 12:15:54.836
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0.103184745 2020.01.16 12:15:55.364
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0.082547791 2020.01.16 12:15:55.875
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0.066038236 2020.01.16 12:15:56.014
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0.052830584 2020.01.16 12:15:56.594
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0.03095673 2020.01.16 12:15:57.516
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0 2020.01.16 12:16:59.505
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0.006105423 2020.01.16 12:17:01.547
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0 2020.01.16 12:17:01.939
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0.006105423 2020.01.16 12:17:02.186
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0 2020.01.16 12:17:02.607
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0.030525208 2020.01.16 12:17:03.447
AHU-C-TR-09 - 2-WayCoolingValveFeedback 0.079365544 2020.01.16 12:17:03.617
AHU-C-TR-09 - 2-WayCoolingValveFeedback 1.09171772 2020.01.16 12:17:12.233
AHU-C-TR-09 - 2-WayCoolingValveFeedback 2.105524302 2020.01.16 12:17:16.164
AHU-C-TR-09 - 2-WayCoolingValveFeedback 3.130450726 2020.01.16 12:17:19.257
AHU-C-TR-09 - 2-WayCoolingValveFeedback 4.216240883 2020.01.16 12:17:22.117
AHU-C-TR-09 - 2-WayCoolingValveFeedback 5.336464882 2020.01.16 12:17:24.591
AHU-C-TR-09 - 2-WayCoolingValveFeedback 6.3889575 2020.01.16 12:17:27.131
AHU-C-TR-09 - 2-WayCoolingValveFeedback 7.391031265 2020.01.16 12:17:28.924
AHU-C-TR-09 - 2-WayCoolingValveFeedback 8.3980093 2020.01.16 12:17:30.724
AHU-C-TR-09 - 2-WayCoolingValveFeedback 9.524324417 2020.01.16 12:17:32.746
AHU-C-TR-09 - 2-WayCoolingValveFeedback 10.68021965 2020.01.16 12:17:34.920
AHU-C-TR-09 - 2-WayCoolingValveFeedback 11.77523994 2020.01.16 12:17:36.813
AHU-C-TR-09 - 2-WayCoolingValveFeedback 12.77749729 2020.01.16 12:17:38.810
AHU-C-TR-09 - 2-WayCoolingValveFeedback 13.8847065 2020.01.16 12:17:40.611
AHU-C-TR-09 - 2-WayCoolingValveFeedback 14.89315987 2020.01.16 12:17:42.442
AHU-C-TR-09 - 2-WayCoolingValveFeedback 15.97050095 2020.01.16 12:17:44.164
AHU-C-TR-09 - 2-WayCoolingValveFeedback 17.06864166 2020.01.16 12:17:46.033

the notes that can be summarized from the values are when the present value more than 1, unsolicited configurations working fine
but when the present value near 0 , archived values fluctuate between 0-1

the questions are:
- is the archived values that are between 0-1 received from the device of the values polled due to some configurations in WinCC because the value near 0?
- how can i prevent this values between 0-1 to be received to reduce BACnet network traffic?

[leoknipp]

The WinCC OA drivers do not change the transfer mode depending on the values received from the PLC.
If you have the values archived it looks like they have been send by the PLC.

Please take into account that an old/new comparison for float values does not make sense if the precision is not limited.
When you want to use smoothing options for float values you should first of all use a message conversion (_msg_conv) to define how many digits after the comma shall be used in WinCC OA. Afterwards the smooting options will use the converted value.
For details please have a look at the WinCC OA Documentation for the _msg_conv config.

Best Regards
Leopold Knipp
Senior Support Specialist