4 wire resistance with HP34401A takes 600ms for 1 measure! run faster?

[marc france]

Hi everyone,

I am using an HP 34401A Multimeter ( through RS 232 ) to make a 4 wire resistance measure every 1000ms (very precisely). However each measure takes roughly 600 ms...Consequently, I don't know when that measure is made (at ,...,300, 400, ...ms?).

Would anybody know how I could solve this problem? Like for example letting the multimeter refresh the measurement as farst as it can ( intern trigger) and labview just reading the value every 1000ms...?  However the measurement would still take 600ms ( I suppose ) ....

Any help would be great,

Marc

PS : If the HP trigger is software and the while loop set to go as farst as possible I can get a measure every 600 ms.... 

        Lowing the precision doesn't make the measure go faster....

        If the HP trigger is "internal" and the while loop set to 1 sec(or as quick as possible) the while loop takes 2000 ms.... 

[AnalogKid2DigitalMan]

No experience with such and didn't look at your code, but have you tried turning off autozero, autoranging, and reducing the number of digits of resolution?

What is the spec for measurement throughput listed in the manual?

[Will.D]

I have used this meter to take measurements myself, and can vouch for it's abilities.  There is definately something wrong with your configuration.

I did not use the drivers written for it, and hence can't say whether or not they're the cause.  Perhaps it may be easier for you to just use VISA.

Try setting the TRIG: DEL (ay) to 0, as well as TRIG: SOUR to IMM (ediate), and also using the CONF: (insert measurement type here).  Using CONF: (...) sets the meter up so that you can just use the READ? command.  Worked for me.

Hope this helps!

Message Edited by Will.D on 10-20-2006 11:19 AM

[ManuelR]

Hi,

It is not useful to create several subjects for the same problem (http://forums.ni.com/ni/board/message?board.id=170&message.id=211603)

I think that it is nor useful ti use the "control mode.vi" at each time. You need to configure it only one time.

You also can try to modify your instrument driver and to delete unused functions which take time. More things you write or read to the serial port, more time it will take.

Hope this helps 😉

[Dennis_Knutson]

It also appears that you are getting 50000 (a five with 4 zeroes) readings each time and then discarding all but the first element in the array. Doing this at 9600 takes a loooooong time and if you are throwing all that data away, why read it in the first place? You might want to spend some time with the manual to determine the optimum settings for speedy transfers and reliable readings. You might also want to consider changing to GPIB or an Ethernet (if available) interface to the instrument.

[marc france]

Hi everyone,

Thanks for ur help. I still haven't found how to make the instrument only make one measurement each time I call it from the while loop, but I'll try to use ur recommendations and tips.

regards

Marc