can you join two hameg dmm's to one labview vi?

[1231]

ok, looks like the vi i got wont do as i need to keep the ammeter constantly turned 'on' as it were, so i would need to join the rs232 ports of two hameg dmms and use one for current and one for volts.

can i do this or identify between the different meters?

i dont think they have unique id numbers??

oh dear, what a mess.......

[Dennis_Knutson]

As long as you have two separate RS-232 ports on your pc, it won't be a problem. Then you identify which one is which by the unique VISA Resource Name each has (i.e. Com1, Com2). You cannot use a single RS-232 port. If your pc only has one, as many new pc's do, you can add an inexpensive USB->RS-232 adapter. Users have reported problems with some brands and VISA though. You should check before you buy.

[1231]

hi dennis

looks like im headin right to the shop now for a 232 to usb converter!

so basically, i can just leave my vi alone, alter the current.voltage part and the com reference?

as for the mean, im sure i can do this on excel itself? once i got time, voltage, current and power im sure excel can gatther the mean ......

cheers pal

[Dennis_Knutson]

Yes, all you would have to do is add a second VISA Resource Name and do a VISA Config Serial Port on the new port. Your wiring, of course would have to be modified to keep the current and voltage functions separate and you would delete any code related to switching back and forth between the different modes.

[1231]

Dennis

i get an error in the scan from string block and the program crashes,

here is my vi in version 7. am i doing something wrong?

[Dennis_Knutson]

What's the error? If the input string is empty or there is nothing in it that meets the scan parameters, you'll get an error. Probe the input to see what it is.

[1231]

Error 85 occurred at Scan From String (arg 1) in gr.vi

Possible reason(s):

LabVIEW:  Scan failed.

thats the error, dont know why its not working, i just hooked up a visa read to each sequence.......

[1231]

when i change com1: and com2: and save it, they revert to com1: when the vi is stopped again?.  both visa configures that is......

[Dennis_Knutson]

A scan will fail if the string does not contain anything that matches the scan criteria. Your format is %f so the scan will fail if there is no number in the input string to convert. You need to probe the VISA Read to see what is actually being returned.

[1231]

its working, relax! just on the jitters here. !

now, i will see if can can export all this stuff 'outside' the loop and save my data, before i could only save stuff inside the loop

do you know if excel can calc the mean of variables, like a row of cells etc?

thanks for all your help