removing data from channel

[jordankuehn]

I have several channels that I would like to remove a fixed number of data points from the start of the channel, basically some data that is recorded during an initialization phase that I don't want included in the data.  Is there an easy way to do this?

[Otmar · Accepted solution]

Hello Jordan,

There is a command that allows you to delete values from multiple channels called DataBlDel

Command: DataBlDel

Deletes a data block in channels.

Call DataBlDel(ChnNoStr, ChnRow, ValNo, [ValDelOnly])

Input Parameters

ChnNoStr	Specifies one or more channels. Channel list variable A channel list is a Channel or Channel list object, or a text that refers to one or several channels. If you use channel numbers or channel number areas to specify a channel list as text, remember that the channels are not always in the order of the channel numbers in the structure view of the Data Portal. If you use channel names to specify a channel area, DIAdem converts these channel names into channel numbers and uses these numbers to specify the channel areas. For more information about the value range, refer to Channel lists. Refer to the Channels and Channel References page for more information about the various ways to specify channels.
ChnRow	Specifies the row number in a channel. Longinteger variable 1 <= ChnRow <= GlobChnLength
ValNo	Specifies the number of values in a channel. Longinteger variable 1 <= ValNo <= GlobChnLength
[ValDelOnly]	Specifies whether DIAdem deletes only the channel values or also all properties when deleting all values. The default value is FALSE which specifies that DIAdem also deletes the properties. Boolean variable

Examples are:

Call DataBlDel("'[1]/Noise_1' - '[1]/Noise_4'",1,7,1)

 or

Call DataBlDel("1-4", 1, 7)

In both examples, seven lines of data are deleted from the first four channels in the Data Portal.

I hope that helps,

     Otmar

[conzemic]

Similar problem, but on several channel groups:

I try to use DataBlCopy (and other data block operations) to run over different channel groups. However, getting the channel strings right is cumbersome. I try with

sChStrSource = "(CH([" & cstr(i) & "]/[" & "cstr(j) & "-CH""" & cstr(i) &"/[        etcetcetc

to get the desired channels j from each group i into a string like

                      CH(" '[1]/[2]' - '[1]/[5]' ")

to pass it to

Call DataBlCopy(sChstr, RowNo, ValNo, sChStrTarget

But I find myself hoping for a better approach. Maybe I was just to dumb to see something obvious.

Michael

[conzemic]

see this thread: http://forums.ni.com/t5/DIAdem/Dynamical-Channel-Selection/m-p/2113396#M15388

Michael

[KyleP]

Hi Michael,

You can see in the Help file for DataBlCopy an example of how they add channels that are hard coded. To get a better idea of how to do things programmatically, as you are, you can see the topic on GetChannels. I think the method you have come up with seems fine, but you are welcome to use the tools provided in the reference parameter of GetChannels.

In the future, please make a new forum thread and reference related posts instead of adding onto multiple threads which have already been marked as solved. It helps keep things less cluttered when people are trying to search in the future

Cheers, 

[jordankuehn]

Forgot to thank Otmar.  That command slipped by me and was exactly what I was looking for.  Thanks!