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LabVIEW DSC Logging too Many Data Points for Integer Tags

Hi,

 

I am having a strange problem with LabVIEW 2013 SP1 DSC data logging, running on XP SP3.

 

All the integer Data Type Tags in my Tag Database that are set to data log, are logging way too much data. When I look at the amount of logged data points for these int16 in Historical view I see its logging a point nearly every second. See screen shots below or attached jpeg's of screen shots of trace view and Trace Props of one of the integer Tags. I would prefer the integer tags to only log on change like the boolean tags.

 

Integer Tag Trace View

 

Integer Tags Data Points Tag Properties.jpg

 

These tags are being acquired from a Horner OCS over Modbus Serial RTU. The Modbus comms is set-up to poll once a second.

The problematic Tag Data Type in DSC logging are Int16

The Modbus register data items denotations I am using for Int16 is S4#####

Example  'OCS_Modbus_Master\S403709' 

The same register represented in OCS Register is shown as '%R0709'

 

The trace properties for some of these int16 tags is showing database page numbers in the thousands, which compared to the largest floating point tag is currently showing 172 pages after several months of logging.

 

I would have expected int16 tags to only log a value when the value changes and since the 'update deadband' tag setting is disabled for integer tag properties there is no way to config the tag to only log on changes. What is the default logging config for integers. Log everything or log on any change?

 

I would prefer for these integer tags to only log on change, since they change infrequently, log on change would be much more data efficient.

 

I tried changing the tag data type to floating point and gave it an update deadband value to try and see if that would reduce the amount of logged data, it didn't seem to make any difference.

 

Not sure if the issue lies in the

> Modbus Comms

> The DSC data event tracking module

> The DSC Data Logging module

> Some kind of  Horner OSC data type mismatch which results in DSC polling seeing the acquired value as having changed on every poll.

 

Any suggestions greatly appreciated

 

Thanks

 

Paul

 

 

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