Problem with scanning Keithley 2700

[Ranj]

I am using Keithley 2700 and communicating with it through GPIB 488.  I am using the example vi's from NI Example finder: Finite Multi Read.vi

I am scanning 2 channels 101:102, the error occurs at the sub vi: Read Multiple direct.vi.  The error message is:

Input string does not contain data in expected format. 

I also get the following errors:

Command Header Error

Expression Error

I have looked at the data using a string indicator i get the correct format  "  ,(@101:102)  "

I also used the single read.vi and this works fine each channel reads the correct voltage no errors occur.

if anyone wants to figure this one out....thank you for your time on this...its appreciated..in advance.

Ranj

[Albert.Geven]

Hi

Can you make current values default and save the vi. And attach it to the message.
You probably have a mistake in the channel list. maybe an extra linefeed or something else special that you don't see.
Another check is the enabling of / code display of your channel list string, nonprintable characters are then displayed.

[Albert.Geven]

Hi

Can you make current values default and save the vi. And attach it to the message.
You probably have a mistake in the channel list. maybe an extra linefeed or something else special that you don't see.
Another check is the enabling of / code display of your channel list string, nonprintable characters are then displayed.

[NathanT]

Hello Ranj,
    I just ran the same example over GPIB and did not have any problems.  I am using LV 8.5.  I tried it with the all of the default values and with 101:102 like you are using.  Are you using the project style driver or the non-project style one?

Looking forward to hearing more,

NathanT

[Ranj]

Hi Nathan

Thanks for your response, I downloaded the project style drivers off the ni website.  The GPIB card is from Keithley and the driver I downloaded is the CEC488 version 8.3, the card and software is quite old.  Therefore the drivers from ni may not be compatiable.  What type of GPIB are you running with your instrument?  The single measurement.vi works perfectly fine without errors so the communication looks o.k when reading one channel at a time.  Any other thoughts are welcome.

Thanks Ranj

[Ranj]

Hi

The data from the Keithley is seperated by commas, this is correct but for some reason the data parsing.vi comes up with the error:

"input string does not contain expected format"

The output of the VISA Read is shown below:

+6.098E+00, +4010.132, +2032, 101

The data parsing.vi selects the first number which is the voltage and the format string function is set to e which is correct therefore the number should be displayed, which it doesnt.

If you have any other thoughts please let me know.

Thanks Ranj

[NathanT]

Hello Ranj,
       I am using a NI-GPIB card, with the current version of the NI-488.2 driver.  I recommend that you try upgrading the instrument's firmware to the current version.  Here is the link on the manufacturer's website.  I will try to take a look at the output of the VISA Read with my 2700 and see if we are getting the same thing.  It is interesting that the first reading that you get is in scientific notation and the other readings are not, I wonder if that is causing the problem?  A temporary workaround if upgrading the firmware does not help would be to change the way that the string is parsed.

Cheers,

NathanT

[Ranj]

Hi Nathan

Thanks for the last suggestion.  I have upgraded the firmware but i am still getting the same problem at the same point.  However, this time the error message i am continually getting is -410 Query Interupted.  This error is occuring in the K27XX Read Multiple Direct.vi.  The parsing of data i am not sure exactly what i have to do...I looked at the code and the string looks right so i dont know what to change...any ideas?

Cheers Ranj

[NathanT]

Hello Ranj,
      Here is the format of my read buffer:

-2.00846279E-03,-3.56483459E-02,-4.80868556E-02,+4.26592492E-02,+1.38128037E-02

So it looks like your 2700 is returning differently formatted values when compared to mine.  Try running the example and set the sample count to a low number, like 10.

What type of measurement are you trying to make?  DC Voltage is what I have been testing with, and I got error -221 when trying DC and AC current.

Cheers,

NathanT

p.s. I have firmware: B05  /A02 

[Albert.Geven]

Hi

looking at the data, I beleive that you are reading different types of values, the last nuymber looks like a like channel number  and maybe a time is also included.
There must be somewhere a switch that removes the extra data overhead.