I am not able to communicate with my instruments

[ramsp]

Hello,
I am a graduate student in India. I
am using NI PCI-GPIB card, which we bought nearly one year back. I am using
LabVIEW 6i. For last two days I am not able to communicate with my
instruments (Keithley DMM 196, Keithley current source 220, Lakshore
temperature controller 93C).
1. I started NI488.2 troubleshooting wizard. It says NI488.2 software
presence verified, GPIB hardware presence verified,GPIB interfaces
sequentially varified. This means Card is alright?
2. I started MAX measurement and automation explorer. It lists GPIB0
(PCI-GPIB) under 'devices and interfaces' folder. After selecting this, If
I click at 'scan for instruments', 'Instruments not found' message
appears.
3. You may say that instru
ments had problem. But the same instruments are
working fine with another system with other card.
4. I agin reinstalled PCI GPIB 488.2 driver from the CD. Now It is listing
three instuments out of four. But the GPIB address for these instruments
are
not same as actual address. It also says instrument didn't reply for *IDN?
query.
5. Everything was working alright, this problem arose few days back
suddenly.

please help me

[AaronK]

Hi ramsp,
This certainly is strange. Especially since it just started randomly. Do you have any other instruments you can try? Also check that your cable is still working fine. It seems like this could be a cable problem as the card installs correctly but you cannot communicate. Do you have an alternate cable? I would also try to connect only one instrument at a time to make the system as simple as possible.

Hope this helps out!
Best Regards,
Aaron K.
Application Engineer
National Instruments

[ramsp]

Dear Sir,
Thanks for kind reply. I have tried both. First for single instuments and second with another cable. Both failed. Ihe same instrument is working fine with CEC 488 PCI card installed in another PC. One more problem, with MAX i pressed 'scan for instruments' I find attached (jpg file) response. My instrument's primary add is 7. MAX is telling that it is 4. How is this possible ?


regards
Ram Shanker

[AaronK]

Hi Ram,
Wow that is really strange. So with the CEC card, your instrument responds at address 7? I am not sure what could be causing this to happen. What happens if you change the address of the instrument? Also can you post an NI-SPY log of what is going on. This might show us where the problem is happening.

One more thing: how old is this instrument? Very old instruments may not respond to the *IDN? command, but this would not explain the apparent address conflicts.

Finally: Does it always (with either cable) detect an instrument at address 4 exactly as shown?

Best Regards,
Aaron K.
Application Engineer
National Instruments

[ramsp]

Dear sir,

Really something surprising. My instument is 'LakeShore DRC-93C'
temperature controller. Probably bought around 7-8 years back.
Here is the actual GPIB add & address read by MAX and correponding
three NI-SPY log.

actual GPIB add*****address read by MAX*****Max Capture(attached files)
25***** 9*****capture_1
21***** 5*****no file attached
20***** 4*****capture_2
17***** 1*****no file attached
10***** instrument not found****capture_3
7*****instrument not found*****no file attached

for first four cases MAX showed 'instrument did not reply to *IDN? query?
Same thing happened when I connected an Keithely Current Source.
(only one instrument is connected,)

actual GPIB add*****address read by MAX

8*****instrument not found
17***** 1
25***** 9

This means MAX is reading GPIB number 16 less than actual Number? Then I tried
to write command at both GPIB address(actual and read by MAX) but both didn't work?

What should I do next?

with best regards
Ram Shanker

[AaronK]

Hi Ram,
Lets try to communicate with the instrument through the IBIC command. My guess right now is that something is not quite right with the card, but lets explore a bit further. To learn more about the ibic command take a look at http://www.ni.com/support/gpib/max/ibic.htm. Lets see if you try to address the instrument directly if that works. If this works, then we might need to uninstall/reinstall MAX/NI-488. It is possible that something got messed up during the install.

Hope this helps out.

Best Regards,
Aaron K.
Application Engineer
National Instruments

[ramsp]

Dear Sir,

I tried to communicate with the instrument through IBIC. The commands and resultant lines are in attached JPG files. I agree with you that something is wrong with the card. It gives EADR error code, which is for GPIB board (GPIB0 or GPIB1) is not addressed correctly. MAX shows GPIB board has address 0. So these two things are conflicting.

Ram Shanker
Ph. D. student
IIT Kanpur, India

[AaronK]

Hi Ram,

At this point the only thing I can think of is to try to RMA the board. If it is not a problem with the cable, it must be a problem in the card (probably in one of the line drivers). Contact your local NI rep in India to set up an RMA.

Sorry for all the troubles Ram.

Best Regards,
Aaron K.
Application Engineer
National Instruments