What is the recommended method for applying limits to a IVI DMM step type

[Yojtotheworld]

I have an NI PXI-4070 DMM, and I want to apply a set of limits to the measurement that is returned, what is the suggested place for inserting these limits.

For example would it be to put a status expression for the step, although this does tend to hide the values from the users.  Any ideas would be appreciated.

[DWeiland]

Hi Yojtotheworld,

    Probably the easiest way to implement what you're trying to do is by adding a Numeric Limit Test step using the "None" adapter directly after your DMM step. You can specify the source of your Numeric Limit Test (Right Click >> Edit Limits..) and either save your DMM results into Locals for the Numeric Limit to reference or point the Numeric Limit step directly to the Results List of the previous step.

A more elegant solution, particularly if you will be using this many times during your sequence, is to create a custom Step Type that encapsulates all you want.

In your Type Pallette (Ctrl + T), for any step type you have the option to "Combine with Step Type...". In your case, create a copy of "Numeric Limit Test" from NI_Types.ini in your MyTypes.ini. (Make sure after you copy the step type again once you create a copy within MyTypes.ini so you don't alter the original Numeric Limits step type). Once you've done this, simply right click and select "Combine with Step Type" and choose the DMM IVI step. This rolls both actions into one step. Again, you'd need to specify the Limits for the Numeric Limit portion to point to the appropriate values within that step.

For more information on custom step types, check out this tutorial:

http://zone.ni.com/devzone/conceptd.nsf/webmain/8329ff7cffe8ae1f86256802007b9824

Hope this helps Yojtotheworld, have a good one.

Dan Weiland
Applications Engineer
National Instruments
www.ni.com/support

Message Edited by DWeiland on 01-10-2006 11:22 AM

Message Edited by DWeiland on 01-10-2006 11:23 AM