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Another Hall Effect Wiring Question and Compliance

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EOtter
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Joined: June 18th, 2015, 5:20 am
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Another Hall Effect Wiring Question and Compliance

Post by EOtter » June 18th, 2015, 5:31 am

Hi,

I currently inherited the following setup:
7001 switch with Hall effect Card 7065
2182A nano voltmeter
6221 current source
6487 --/voltage source

We are trying to run low resistance measurements on thin films. Currently we have a collinear probe and eventually want to go to Van der Pauw application. The units are configured with the 2661 output to the 7065 imput, the 7065 output to the 6487 input, the jumper from lo to lo from the current source to the ammeter, and the ch1 wiring from the voltmeter to the 7065 with of course the probe inputs into the 7065. I closed the appropriate cross points according to the manual, but everytime I operate the current source, the unit goes immediately into compliance. I have it set with a current of 10mA and a compliance of 10 V so it shouldn't be a compliance setting issue. Clearly there is a fault in the circuit but I am unsure as to where. Any ideas that would cause this? I want to make sure the wiring and everything is correct before I worry about the probe itself.

Thanks.

Dale C
Keithley Applications
Keithley Applications
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Re: Another Hall Effect Wiring Question and Compliance

Post by Dale C » June 18th, 2015, 6:24 am

Can you remove the 7065 card from the circuit and just connect a resistor to the output of the Model 6221?
This would verify the Model 6221 is operating properly.
If it is, then we need to look at the configuration a little closer.
Can you post a block diagram of what you are trying to do?
And maybe and schematic of how it is wired?

EOtter
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Joined: June 18th, 2015, 5:20 am
Country: United States

Re: Another Hall Effect Wiring Question and Compliance

Post by EOtter » June 18th, 2015, 12:02 pm

I tried to test the 6221 using this method found on here:

1. Voltage source HI is connected to one side of the resistor.
2. Input HI(Inner conductor of the triax connector) goes to the other side of the resistor.
3. Voltage source LO is connected to Input LO(Inner shield of the triax connector).

I still got the compliance light at start up. I did my best to make the connections. A block diagram is attached here.
7065Setup.jpg
7065Setup.jpg (32.78 KiB) Viewed 27873 times

Dale C
Keithley Applications
Keithley Applications
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Re: Another Hall Effect Wiring Question and Compliance

Post by Dale C » June 19th, 2015, 7:01 am

Thanks for the diagram.
The procedure to test the resistor is wrong.
Just connect the resistor across the HI and LO of the current source.
Then apply the current and see if it goes into compliance (blue light blinks).
The method you mention is for a source voltage measure current type of technique.
That would be if you are just using the Model 6487.
I suggest you watch the Hall effect video.
It is on the KI site. Here is the link.
http://www.keithley.com/centralized_dis ... etid=55820

EOtter
Posts: 4
Joined: June 18th, 2015, 5:20 am
Country: United States

Re: Another Hall Effect Wiring Question and Compliance

Post by EOtter » June 22nd, 2015, 8:21 am

Okay using that method, the current source functioned properly and did not go into compliance.

I have watched the video a couple of times now but thanks for the help.

EOtter
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Joined: June 18th, 2015, 5:20 am
Country: United States

Re: Another Hall Effect Wiring Question and Compliance

Post by EOtter » June 23rd, 2015, 11:47 am

Looking back on this, I'm not sure I was completely clear. The resistor test did show that the current source was functioning correctly but we are still getting a compliance error with everything back together.


Thanks

Dale C
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Re: Another Hall Effect Wiring Question and Compliance

Post by Dale C » June 24th, 2015, 8:42 am

Then I would revisit the crosspoint closures.
Either they are the wrong crosspoints for this measurement or the relays are not closing.

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