Error - 1074126845 at NI-DMM read multi point.vi

[alexndr]

I am running one of National Instruments example programs that I have downloaded from the website identified as 1634.vi.  This example program allows you to perform different measurement types on different channels of a switch . The number of channels specifies the number of samples that the DMM acquires. 

         If more than one channel is specified per different measurment type I recieve: Error -1074126845 ocurred at NI-DMM read multi point.vi.; Explaination: Max time exceeded before operation complete. 

         I have a PXI-1000B chassis, a PXI-4070 DMM, and a PXI-2530 switch matrix configured to a 2-wire resistance measurement.  The DMM is located on slot 2 and the switch matrix is located on slot 8. 

         I have tried to switching the trigger lines because this programs runs on handshaking and the same error occurs, any help on this situation is appreciated.  Thank You.

[Jeff_T.]

Hi alexndr,

I was also having some difficulty running this code, but I did not experience a timeout error like you described until I deleted the Abort Scan.vi from the switch function calls.  I was able to get this example to work correctly by leaving the Abort Scan.vi and inserting an niSwitch Set Continuous Scan.vi right after I configure the switch scan triggers.  

Please give this VI a shot and let us know how it goes.  If you are still experiencing problems could you please tell us what version of the drivers you are using, if the DMM/Switch passes a reset in MAX, and if you can operate the DMM with its Soft Front Panel.  Thanks and good luck!

Best Regards,

Jeff Tipps
Applications Engineer
National Instruments

[alexndr]

Jeff T.,

          I really appreciate the help this did rectify the problem.  Thanks Alot!!

[R1R]

Dear Sir,

Is this program meant to take continuous reading? I have 1 channel in each section of scan list. I want it to "continuously" taking measurements from the specified channel. So it goes like this: a - b - c - a - b - c - a - b - c -......................... and so on. I tried putting the same block diagram into a while loop but the channel does not repeat to the same one. Because I only specified 1 differential channel in each section, so it gave out error message, such as no scan list found.

Please help.

Thank you.

Ryana

[Corby_B]

Hello R1R,

Thanks for your post!

The example that the above posts are using is great if you need to switch scan lists. There is an example program in the LabVIEW example finder that is great for continuous scanning. Its called niSwitch DMM Switch Synchronous Scanning.vi.  You can find this example by going to the example finder in LabVIEW, Help >> Find Examples. Then navigate to Hardware Input and Output >> Modular Instruments >> NI-SWITCH (Switches) >> niSwitch DMM Switch Synchronous Scanning.vi.  This will allow you to do a - b - c - a - b - c - a - b - c -......................... and so on continuously until you specify to stop. The 1634 example could also be run continuous if you replace the for loop with a while loop. I have not tested this as I do not have a switch DMM setup but it looks like that could be done.Let us know if this helps you with you questions/concerns.

Cheers!

Corby_B

http://www.ni.com/support 

[R1R]

Hello Corby,

Thank you for your reply. That was quick! 😃

I have actually done that (replacing the for with while loop) but it failed me. It sort of continue to the next in my scan list which is nothing since I only put 1 channel for each section. I only have three channels that I want to measure, and I put one in each section. I know that I can just use one section for all those 3, but I'm measuring 3 different things (voltage, temperature and current), so I thought that would be easier to see. I need it to go back to the first and the only channel in the list. I'll try that example first.

Another thing is that I don't know which data line to get the waveform chart. I want all the channels to show up in the chart. Not sure how to do that, since I'm completely new in LabView. I also want to process the data according to boolean logics, and perform different things, such as switching on/off relays that are connected to my DIO (PXI 6514) according to the limit values that I provide through the logics.

Thank you so much!

Ryana

[Corby_B]

Hello R1R,

Thanks for your post back!

So in fact you could just put a while loop around the entire program and that would allow you to run continuously. So leave the inner loop as a for loop because you would only want that loop to execute 3 times as you only have 3 different channels that you are working with. If you decide you need more channels later you can always increase the for loop iteration.

As for the graphs you can get the data from the output of the DMM read VI and feed that to the charts. You will need to index the data to display the different data sets to different graphs because since you are measuring 3 different kinds of readings you will need 3 different scales. See the attached picture for how to do this using the index array functions. Let me know if this helps you with your application. Have you ever thought about  taking a LabVIEW basics course? We teach them all over the United States.

Cheers!

Corby_B

http://www.ni.com/support 

[R1R]

Heya Corby,

Thank you for your answers. I think that will definitely work. 

I did the Intro to LabView Hands-on course over here in Sydney, like 4 or 5 months ago. There were not much useful information, except that I became not that awkward anymore in handling LabView. There are probably some other courses offered, but I'm not aware of it. 

Anyway, thanks so much! I'll post again of how it goes.

Ryana

[R1R]

Hey Corby,

It's working good.

Thank you so much

Cheers,

Ryana

[fr@nk]

Hi Jeff,

I'm trying to do a high count switch project and was looking at using 1634.VI as a place to start for part of it. I'm having the same problem as Alexndr and I tried the fix you suggested to him without success.

I ran the VI without modifying it first (except for the functiontype and number of items in each scan list. The 3 clusters consist of 5, 4 and 3 scan items, all measurements are 4.5 digit / 4 wire resistance. Item 1 of each list includes the same terminals, as does item 2, etc. with lists 2 and 3 just having fewer items). It successfully collected data from the first scan and failed at the AbortScan via at the end of the first For loop. The error message said the scan could not be stopped because no scan was currently happening.

I added a ScanContinuously VI after the ConfigureScanTrigger VI and before the Foor loop left edge and the error source and message was the same. I move the ScanContinuously VI into the For loop. This had no effect.

I was looking at the SwitchInitiateScan VI context help. It says that it commts the hardware settings (if not aleready done) and starts the scan. Once the scan begins no operation can be performed until it ends except AbortScan, SendSoftwareTrigger and retrieval of attributes. It says to use the AbortScan VI to abort a scan.

It seems as though the scan should be finished when the scan list has been processed and the Switch/DMM handshaking is over and that a new scan would begin with the next iteration of the For loop.

Can you explain what is really going on it this example?

I tried removing the AbortScan VI and got the following. The first iteration of the Foor loop executed with no errors. The resistance values were: 0.5408Ω, 10.7786Ω, 119.7420Ω, 1236.374Ω and 11846.28Ω. The second loop failed for a DMM ReadMultipoint timeout error and provides outputs of 1236.374Ω, 0.0000Ω, 0.0000Ω and 0.0000Ω. So the fourth (last in list #2) scan item was only one that was exexcuted. I'm assuming that zeroes were returned for points that did not get executed. Is this a clue to what is going on?  

I noted your request before for the driver versions if your solution didn't work. I'm using NI-DMM 2.9 and NI-SWITCH 3.8, all running with Labview 8.6 Full version.

Thanks,

Frank