Programmatically modifiying I/O type filtering

[banksey255]

Hello,

Is there a way to programmatically modify the physical channel control I/O filtering?

DAQmx, which ULx appears to be modelled on, offers this capability through property nodes (see screenshot below), yet ULx does not appear to.

If this capability does not exist, can it please be added? Without it, it requires one physcal channel control per I/O type and port/line filtering, which can amount to requiring many controls (ULx filters between 18 different I/O type and port/line filtering, thus, at present, it requires up to 18 physical channel controls). It would be much simpler if a single physical channel control could be used whose I/O filtering can be programmatically modified.

 

 

[JRys]

Hello,

It is not possible to programmatically create channels of different types in a structure such as a For loop. It's possible to simplify channel creation by specifying a range of channels in the ULx Create Channel VI. For example, the Create Channel Analog Input VI Physical Channel control can be set to specify multiple channels. The string "Dev0/Ai0:15" would add 16 channels with a single Create Channel VI. Only when a channel is to use a different voltage range would a separate VI be needed . In this case,  the VI's could be placed in series with each other. The user interface could also be used to select multiple channels. Select Browse from the channel list then using the CTRL or SHIFT key, select the channels or group of channels you wish to create. Of course, if there will be Analog In, Out, Digital In, Out and Counter In, Out you will need separate VI's. Perhaps it is this way because our devices tend to be lower cost alternatives and have fewer channels and features than NI's offerings. Or it could be because ULx channels cannot be reprogrammed during run time without clearing the task.

Best regards,

John

[banksey255]

Hi John,

You appear to be addressing something else. I am aware there are limitations with your hardware with respect to acquiring data from channels with mixed measurement types, which is described in the ULx for NI LabVIEW help in the known issues section. Having said that, your help document does state some of your hardware supports composite tasks, and I have noted that composite input and composite output options exist as polymorphic instances of the ULx Create Channel VI. In any case, I do not believe the hardware I am testing my application development with has such capability (USB-2416-4AO), however I have observed that your DAQami application is able to acquire data from multiple measurement types from the hardware I currently have available, albeit perhaps it achieves this by creating separate parallel tasks (it's not something I have looked into, but I can see in DAQami that the sample rate limits differ for analog, digital, and counter, which suggests that it does create separate parallel tasks).

To try to clarify, my forum post is motivated by wanting to create a user interface that can work with any I/O types as I will not know this information apriori (that is, it must be customisable). At present, it appears (although please correct me if I'm wrong) that the only way I can do this is to have one physical channel control for every concievable I/O filtering option. It would be much simpler if I could programmatically create my own equivalent of your ULx I/O Name Filtering dialog so that the user can change the filtering in the deployed application to match their physical setup as that would permit a single physical channel control to be used, rather than requiring many physical channel controls. To try to be more clear, here is a screenshot from what my current user interface looks like (refer to the central column), where my idea would be the appropriate I/O type filtering of the Physical channels control is programmatically set based on what option the user selects in the Measurement Type control (the user specifying channels is completely separate from where I actually configure hardware, and I separate channels into groups as necessary in between, for instance, to satisfy any hardware constraints on composite tasks):

Best,

Stephen

Edited November 28, 2022 by banksey255