Trying to measure voltage through 1 wire connection

Hai ,
       I am trying to measure voltage through 1 wire connection using NI hardwares like  1)chasis SCXI-1000   2) DMM PCI- 4060, 3) MUX SCXI-1127 and 4) Terminal Block SCXI-1331. Please see a attached picture of my set up.
  I am unable to establish my connection through  1_WIRE_LO_REF .I want to use it  as my reference point (GND) through which I can measure the voltage .I think there may be problem in my design or in the labview code.Could u please verify   and suggest the appropriate one.
Can I use 1_wire_Lo_ref is so which port to be used, actually i have six ports for this point (or) is there any altenative
 I hope u respond soon and in the affirmative
with regards
madhava
Attachments:
Scanning_of_SCXI-1127_48_write.vi ‏144 KB
IM0000041[1].jpg ‏722 KB
IM0000041[1]1.jpg ‏722 KB

Hi Madhava,
Are you unable to get the example program to work?  Are you using an Aux cable to connect the switch to the DMM or are you triggering from the connector block of the switch?
One good resource is to open the NI-Switches Help from Start >> Programs >> National Instruments >> NI-Switch >> Documentation >> NI-Switches Help.  Go to the Search tab and search for Single Module Scanning - Handshaking.  There are sections for SCXI or PXI depending on which form factor you are using.  This will explain which triggers to use and how to connect the DMM and Switch together.
In the same help file, if you search for Scan Lists, this will show you the proper syntax for the scan lists.  The scan list can all be listed in one text box and does not have to be an array of strings. 
I think the best way to proceed is to take the example that I showed you save it as a new program so you can go back to the original if you need, make it work and then modify it to do what you need.  Add the write to file for example.  If you have any questions about specific issues, I can help you with those.
Thank You,
Nick F.
Applications Engineer

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    We have NI hardwares like: 1) Chasis SCXI-1000, 2) DMM PCI- 4060, 3) MUX SCXI-1127 and 4) Terminal Block SCXI-1331
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    Another thing, in one of my previous contact with NI someone mentioned connecting 1_WIRE_LO_REF. Is it needed in this case? If yes, then if I connect one end to 1_WIRE_LO_REF, where should I put the other end?
    In case the program is wrong or more than 16 values can not be taken please let me know alternate path or show me how to make changes in the program. I would appreciate your help in this issue. Thank you.
    Message Edited by ERT_LSU on 09-17-2007 12:16 PM
    Attachments:
    Scanning_of_SCXI-1127_48_write.vi ‏144 KB
    IM0000021.jpg ‏767 KB
    IM0000041.jpg ‏722 KB

    I connected the COM of my power source to the 1_WIRE_LO_REF. There are 4-5 points to connect. I choose the middle slot. Is there any significance of assigning so many slots to 1_WIRE_LO_REF?
    No change in result. Can you please test run the program I attached and see whether it's correct or not. You'll see 48 segments getting the output. First 16 of them are showing some seemingly proper values. rset are either too small or as big as 5 V.
    I'm providing 5Vs from the power source. You might have seen the old analog ones. I'm using one of them. there are different Voltgae option. I'm using the 5V and so I've connected a wire from the 5V connection to one of the electrodes on B side (28th electrode) and the COM ports goes to the A side (4th electrode) and also to 1_WIRE_LO_REF.
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  • Trying to measure voltage through SCXI-1127/1331 2-wire connection [ Edited ]

    Hai ,
         this is madhava from LSU,I am working on ERT with  NI hardwares like 1)chasis 1000 2) DMM PCI-4060  3)  SCXI -1331(2 in number)
          I have a system with two large glass plates standing vertically and placed parallel to the user.I am trying to flow different liquids of density through the channel in between.Please  see a attached picture of it.
        There are total of 48 electrodes 24 on each side to which wires are connected. On each side there are 3 rows with 8 electrodes/row, say 1-24 on side A and 24-48 on side B. The medium between the two sides is salt water.
         I want to measure the potential in such a manner that  I can calculate the voltage difference between all possible electrode combinations between side A and side B.I have connected a  two end power source to side A and side B, i.e. +ve to side A and  -Ve to side B , so   the  electrode on the A side acts as the "source" and the electrode on the B side acts as "sink".
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        I tried it with 1  SCXI - 1331, but did not get proper values.So what do you suggest shall I continue this with the 1  wire or could you please help me with the two wire experiment, so that I can get more combinations.
               I hope you respond soon and in the affirmative.
    With regards
    Madhava
    Attachments:
    Scanning_of_SCXI-1331_48_write.vi ‏144 KB

    Welcome to the discussion forums, Madhava!
    The optimal solution is to have a 2x48 (or more) matrix so
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    Mark E.
    Precision DC Product Support Engineer
    National Instruments
    Digital Multimeters (DMMs) and LCR Meters
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