How to measure insulation resistance using agilent 34970a...

[NewInLabVIEW]

Hi,

I am using Agilent 34970a for measurement of insulation resistance. I have to develope a test automation software which will test insulation resistance between a +ve test lead and bunch of -ve leads. Both, +ve and -ve test points will change for next measurement. So, bunch of -ve test pins i can specify as scan list to Agilent 34970a but what about +ve test lead. How do I configure it??

Generally, we provide scan list and it will scan these channels to measure resistance. So it will be using some reference point and channels from scan list to measure it. Actually, i have to configure this reference point as one of the channel.

1) Can we configure this reference or +ve test point as one of channel of Agilent 34970a through programming interface?

2) Is it possible to use one of the channel from scan list as reference point. If yes then how can it be achieved?

I hope, I could communicate what I wanted to...

Thanks & Regards,

Nilesh

[Dennis_Knutson]

First, since this is not an NI Multifunction DAQ device, you posted to the wrong board. You should use the Instrument Control board in the future.

Second, what switch card are you using? The 34901 and 34902 are two wire switches with one wire connected to DMM+ and the other to DMM- so you only specify a single scan list.

[NewInLabVIEW]

Hi,

I will keep in mind from next time.

I am using 34901A module. Suppose, I have scan list as {1,2,3,4,5} . I have to measure resistances for all possible and allowed combination of pins i.e.

1-2, 1-3, 1-4... then 2-1, 2-3, 2-4... then 3-1, 3-2, 3-4... so on

So for first channel sweep, to achieve 1-2, 1-3, 1-4..., scan list will be { 1 (connected to +ve wire of ch1 ),  2(connected to -ve wire of ch2), 3(-ve ch3)....},

     for second sweep, to achieve 2-1, 2-3, 2-4... I will change the connection, scan list will be { 1 (connected to -ve wire of ch1 ),  2 (connected to +ve wire of ch2), 3 (-ve ch3)....} and so on

I just want you to tell me if i understood it correctly. I have attached one diagram, i drew to show this.

Thanks,

Nilesh

[NewInLabVIEW]

I also have one question. Suppose I have inserted 34901A in SLOT1 and SLOT2. I connect pin 1 to +ve wire of ch1 of SLOT1 and remainning pins to -ve terminal of SLOT2 channels. My question is, "Will I be able to achieve 1-2, 1-3, 1-4... resistance measurement in this case too" ?. Actually i have to implement it in this way all +ve terminals in SLOT1 and -ve in SLOT2.

[Dennis_Knutson]

I really don't understand what you are doing. You said you needed to measure the resistance between a +ve and a -ve. You would connect +ve-1 to ch1H and -ve-1 to ch1L. +ve-2 to ch2H, -ve-2 to ch2L, etc. If your requirements are different than something this simple, you should probably be using the matrix switch.

[NewInLabVIEW]

Let me give you some details about what i have to implement. I have J1, J2, J3, J4, J5 and J6 connectors on some device. Each of this connectors has set of pins.  J1 connector has {1, 2, 3, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 18, 19, 20, 21, 22} and J2 has {1, 2, 3, 5, 6, 8, 9, 10, 11, 12, 15,18, 19, 20, 21, 22} set of pins. Similar for other conectors.

Now, I have to use Agilent 34970 or any other capable instrument to measure the insulation resistance for this connectors. So, for connector J1 pins i have to check resistance between all possible pin combinations, like between 1-2, 1-3, 1-4..     2-3, 2-4, 2-5    3-4, 3-5 3-6...   and so on.Similar measurement for other connectors.  Its like, each time taking one of the pin from connector as reference and measuring resistance between this reference and remaining pins one by one.

As, i have to implement the automation test software, all the setup will be done at one time (before test begins). This software will maintain all resistances measured for these conectors. Currently i have to select an instrumrnt which i can use to implement this.

I hope, I could explain properly this time.

So, I was going through Agilent 34970A document. 34901A and 34902A modules can be used to measure resistance, but i am not clear that what i need can be achieved using these modules.

[Dennis_Knutson]

No, the scanner cards cannot do this. You would need a matrix where each column is connected to a pin and two of the rows connected to a dmm. You cannot connect to the internal dmm of the 34970 with their matrix card and I don't know if a unit can hold enough cards for all of your connectors.

[NewInLabVIEW]

Thanks, I will not focus on scanner cards now. 

But in case of 34904A matrix switch, it is also 2-wire columns and rows. I have attached a snapshot showing it. Do you mean that using only +ve terminals of columns and leaving the -ve terminals open and then connecting DMM (external) between +ve terminals of 2 rows.