How to increase measuring speed of Agilent 34401A

[coolmicky]

The process of my program (written in Labview) is:

1) A control code is automatically generated by the program, and the code is sent to multiplexing circuit (the chips I used are ADG706) through digital port (USB6501 from NI)  then a coresponding channel is selected. (for example code hex0000 selects 1st channle,0001 selects 2nd channel, and so on......)

2) Multimeter Agilent 34401A measures the current value of this channel, and send this value back to the computer for storage. After this, the program goes back to step 1) for next channel, and this program executes like this.

The functions mentioed above are all realized, and the program works well, but the problem is the speed is slow. It takes a little more than 1 second to measure one channel, totally I have 2048 channels (32 groups and 64 channels in each group, I used two layers of "for" cycles), and it takes about 32 minutes to finish measure all these 2048 channels, too slow, I'd like to reduce them to 10 minutes.

I tried to reduce the resolution to 4.5, turn off the autozero function of multimeter, but nothing happens, no change of the speed. Now every time the multimeter measures a channel, it makes a "click" sound, does it mean that every trigger the multimeter only takes one measurement? Is there anyway I can increase the measuring speed? Can I send the multimeter 64 control condes a time, and then let the multimeter takes 64 measurments in one trigger? Is it right? If so, how can I realized it?  If I'm wrong about it, can you give me some solutions?

Thank you very much! 

[Darin.K]

I don't have the manuals with me, but I do have a couple of these in my lab.   There is an internal buffer where you can store (I think) 512 readings.   You can use a digital output to trigger the DMM, and only transfer after every 512 readings (4 times) or perhaps one read per group as you mentioned.  I suggest one read per trigger (you can do many more) since it is easier to synchronize with your channel changes.  I believe the commands are INIT and FETCH?, check your manual.  The two times I know the instrument "clicks" are changing functions and certain range changes.  I suspect in your attempts to speed things up you are sending some config. commands each time.  Configure it once initially and make certain you are only sending measurement related commands during the scan, any config. changes (even if you resend the current value) will likely cost you time.