Multithread Voltage/Current Check using 2sets of DMM

[Umaga]

Hi..

I need some fresh idea on how to solve my problems. I've been using Labview for about 3years now.

Currently I'm trying to modify my current VI for multithread check. Last time my VI can read from only one Digital Multimeter (DMM) and now i want it to be able to read from 2 sets of DMM so that the process can run in parallel & execution become faster. Have any experts out there tried this method before. Some suggest me to put the block diagram in parallel so that the data can be execute at the same time. Is this true?

I've read through all the thread but can't found the answer I'm looking for. There are suggestions from others to use TestStand but I'm not familiar on how to use them. Plus I don't want to make big modifications on my current hardware designs.

Attached together is sample of my current VI using only 1DMM. I welcome all to give any suggestion and opinion for easy way to perform multithread check for my case. I'm using Labview 8.5 so please let me know if you can't open them.

Thanks and Regards,

Allen

Test Equipment Engineer

Sony Corp.

[KateB]

Hi Allen,

Since you don't share its block diargram, I cannot share much information.
However, basically, just separate acquisition loop for each instrument will separate the core already.
But be careful not to have shared resource between loop, since it can be a bottle neck.

Regards, Kate

[Dennis_Knutson]

Since you have the block diagram password protected, could you at least provide some information on how you are connected to the DMMs? If it's GPIB, you certainly cannot write/read in parallel except in certain circumstances.

[Umaga]

To Kate & Dennis,

Sorry for the trouble. I forgot to remove the password. You may unlock using this password "mepowerrr'. Can you guys give me suggestion based on my current block diagram.

Btw, I connect to DMM using USB and GPIB through VISA. I control the DMM by creating an instrument file within my application. The instrument file is different for each DMM. Try to make my program suitable for all type of DMM (Agilent, Tectronics & Fluke). Now I just worried thinking if its possible to do multithread check on my application.

Is there an easy to do this?

[Dennis_Knutson]

That password does not work so why don't you post the unlocked VIs?

[KateB]

I guess you will just duplicate display detail for 2 DMM.

Well, even you can parallel task for string manipulation to utilize multicore, but the real problem comes from GPIB communication which still shares the same GPIB controller.

If you don't use multiple GPIB controller, you'll not see a significant improvement by separating the loop, since they still share the same hardware resource.

[Umaga]

Kate, I'm guessing you managed to open my block diagram. Correct, my plan now is also to duplicate the display_details vi so that it can manage multithreading. What do you mean by multiple GPIB controller? Of course for 2 different DMM I need to use multiple GPIB controller. Problem is I'm just not sure whether the application can read data from 2 DMM at the exact same time.

It would be great if there is others who already tried this method can share some findings.

[KateB]

You actually can connect up to 14 instruments using single GPIB controller, but of course, they cannot work parallely.

Using separate GPIB controller for each instrument can make them work parallely, but it doesn't synchronize them which means that you'll not get exactly the same measurement point in time, but this doesn't sound like your objective.

I think you only need them to work in parallel to increase the speed, right?