Can "Hold Control" be used to start and pause data sampling?

[gary14]

Hi,

I currently have some data sampling objects I want them to start and pause sampling when I start a pump and stop it, but I want it to keep writing the data into the same file.

My question is, is this done using the HOLD CONTROL feature when setting up a new data sampling object?

Thanks

[Brendon.S]

Hi @gary14,

That is correct! Here is a detailed explanation of the “Hold” address within our data sampling tutorial: Click Here

[gary14]

Brendon,

I went thru the video very informative thanks.
But I need a clarification.

If I am using the hold control will allow me to pause and resume data sampling on the same file.
My question is if I had customize file handling it will create a new file every time I trigger the data sampling on ?

Also, is there a bit I can trigger to delete all of the stored data logs?

Thanks

[Brendon.S]

When using “Customized file handling” the “Hold control” address will not create a new file each time it is triggered. To create a new file, the “File creation” condition must be met. While “Automatic mode” is selected the files are named according to the time syntax used within the “Format” box. When the name changes (e.g. the date or time) a new file will be created automatically.

While “Trigger mode” is selected, a new file will be created when the corresponding trigger condition is met.

To find the system bit that is associated with removing all retained data sampling logs, please perform the following:

1. Select the “Project” tab and click “Address”:
   
   
2. Select “System Tags” and enable “Classification”:
   
   
3. Select “Data sampling” and identify the system bit that corresponds with the location that your files are saved:
   
4. Trigger the appropriate bit within an external object or macro to delete all data sampling files.

[gary14]

Brendon,

Thanks got it working the way I need it to.

Last questions I have the trending display object, it is working showing data , but the date and time is off I’ve checked the system parameters time sync/DST and I do have it set to my correct time zone (-8:00 pacific time) but the time on the trending display and the excel file created it wrong, any ideas ?

Also is there a way to leave the Y scale always enabled on the trending display or is it something that needs to be turned on every time the HMI’s restarts

Thanks

[gary14]

Found the cause of the wrong date/ time in my trending display
Server response time was set to -8:00 instead of GMT standard time

[Brendon.S]

I am happy to hear that you were able to resolve this issue. Regarding your question about Y scales, the Y scale can be enabled for any channel prior to download by selecting a Y scale position within the Y scale tab:

1. Within the Y scale tab click on “None” within the Y scale column:
   
2. A drop-down menu will appear and you may position the Y scale on either the “Main” axis or an “Auxiliary” axis:
   Note: Grid must be enabled to use this feature.
   
3. The “Main” axis is the axis that is closest in proximity to the display region:
   Example: DP101 is the “Main Axis”.
   
   
   
   Example: DP202 is the “Main Axis”.
   

This setting will display the Y scale at boot, it can be disabled or re-enabled within the trend display’s option menu on cMT HMIs during runtime: