In Circuit Test (ICT) in Teststand

[MechUnit]

Hello Community,

I am using NI PXI equipment with Dev Suite 2012 with Teststand/Switch Executive for a dual stage test fixture (ICT & FCT).

Are there any methods or software by NI or third parties for developing the ICT portion of my test process easier? NI does a great job with functional test, but is there a good way to do ICT?

Currently I am using a DMM, Switch Card, and Guard Amp. Writing a bunch of lines of code in teststand to toggle the switches on the card. Was wondering if there was a simpler way.

Thank you,

Kevin

[KyleP]

Hi Kevin,

Could you be more specific with what you would like to do in ICT? What are you looking to do differently than FCT where you think it might cause difficulties?

Cheers,

[MechUnit]

I would like to be able to read the values from an excel spreadsheet into a VI. Create a Teststand Pass/Fail Sequence with one line of code using the VI.

The VI will have a For Loop that runs down the list of my spreadsheet. It will read R1 from the list, toggle the switches and guard amplifier on for R1 at the specified test points, take a measured reading, compare the measured value to the value range (900 to 1100 ohms), and return a result of pass or fail.

Example Spreadsheet:

ID	Value	Test Point 1	Test Point 2	Type
R1	1.00k	TP1	TP2	Resistor
R2	10.0k	TP3	TP4	Resistor

My reasoning behind this is to standardize an ICT procedure with teststand. To be able to add and edit resistors or capacitors to be tested straight into the spreadsheet instead of the method I am doing now which is time consuming and messy. For each resistor I want to test it takes me about 5 lines of code to setup in teststand... 

Connect Switches

Connect Guard Amp

VI Numeric Limit Test

Disconnect Switches

Disconnect Guard Amp

I am open to suggestions, if there is a better way to do ICT or a way to speed up the process & setup of those 5 lines above? It just seems like doing ICT with NI Equipment is tedious.

[MechUnit]

What is the easiest and best way to go about testing roughly 50 resistors on my PCB for the ICT using Teststand?

[KyleP]

Hey Kevin,

I think what you're looking for is NI Switch Executive. Take a look at that document and see if that seems to tackle the problem you're after.

Cheers,

[RaviShrigiri · Accepted solution]

Few suggestions :

1) Use switch executive to connect all the switches in a single go ( refer examples).This will probably reduce from 5 steps to 3.You can refer the link already provided.

2)Using the C language function approach - create a sub sequence which tests a single resistor :

i.e.

sub sequence : R_test(Rname,Rvalue,Rswitches,etc) --- the arguments or parameters to this sub sequence taken from spread sheet.

Typical Steps in sub sequence :
a)Connect all switches --- based on the switches argument
b)Pass fail test - call VI which does the testing and returns pass fail
c)Disconnect switches

3) In the main sequence you just need to call this sub sequence for each resistor.

4) The other approach wherein you want to load your requirements from an excel sheet please refer property loader step type and its examples.

For this alternate approach :

You can create a container of Type R with variables- R.value,R.name,R.switch1toOn,R.switch1toON,etc.

Then you can create a array of Type R and export to an excel sheet using import\export tool ( tool menu) ( take max 100 more than u want)

In the excel sheet you can update the R values.

You will also need one more variable noofresistors which is in the excel sheet.

Your main sequence can be like this :

property loader step type - upload all the container values and noofresistors from excel sheet to Teststand variables.

For( i=<noofresistors...)

{

call sub sequence for R checking with parameters (array[i].R)

}

In the above example you need not change the sequence at all...only update values in excel sheet.

Hope this helps.

[MechUnit]

Thank you SunRS . Your suggestions helped me cut the steps down in Teststand and with the Property Loader I am able to bring in my excel spreadsheet without having to create another VI. Now I have parameters in Teststand as an array from my spreadsheet.

The guard amp is also being toggled on/off from the switch card. So I believe I can cut those additional steps down too by making a function to connect both my switches and guard amp.