Using GPIB-USB-HS connect power supply PST-3202 can't respond *IDN?

[neo_lee]

Using GPIB-USB-HS connect power supply PST-3202  can't respond *IDN.

But using GPIB-USB-B connect power supply PST-3202  can respond *IDN.

What's wrong with GPIB-USB-HS?

[MichaelChaney]

Are you using "*IDN" or "*IDN?"  If the instrument is found when scanning from instruments from MAX, and it does so without returning an error, then the GPIB interface is working correctly.  When scan for instruments is called, MAX sends *IDN? to all devices and returns an error if a device is found that doesn't respond to *IDN?.  Can your device respond to any other commands?  The GPIB-USB-HS if fully backward-compatible with non-high speed devices.

[Tim Povlick]

We are having the same problem.  Power supplies, Instek model PSS-2005 and PSM-2010 work fine with the GPIB-USB-B device but not the GPIB-USB-HS device.  Using the NI Measurement and Automation Explorer -> Devices and Interfaces -> GPIB0 (GPIB-USB-HS) when searching for instruments it hangs for a long time and doesn't find the power supplies.  With the GPIB-USB-B it finds them pronto.   Other instruments (Agilent, TEK) work with either -B or -HS.

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Tim

[MichaelChaney]

Hi Tim,

There are some very slight timing differences between the -B and the -HS, but both are within 488.1 spec.  One thing you can do is to post a NI-Spy capture so that I can have a look at what's going on when the error occurs.  More than likely you are getting a timeout error, but this will tell us for sure:

http://digital.ni.com/public.nsf/websearch/8D890EC09B15C05A86256E6F007E3E86?OpenDocument

I haven't heard of problems with Instek instruments before, but this might be the first time this problem is showing up.  What concerns me is that you are not having any problems with Agilent or Tek devices, but are having problems with multiple Instek devices.  It's possible that there might be a firmware issue with the Instek devices.  I would definitely contact them to find out:

http://www.instek.com/contactinfo.html

Instek advertises both devices to be 488.2 compliant, so they should respond to the *IDN? query that MAX is sending out.

[Tim Povlick]

Hi Michael,

I ran the NI-Spy program and indeed a command is timing out.  Once this happens I have to power cycle the supplies.  If I run the Measurement & Automation program, scan for instruments,  it eventually finds the two power supplies.  I then power cycle the supplies to clear them.  From the 'communicate with instrument' I can hit the PS with *IDN? and it responds correctly ("GW.Inc, PSM-20...").  If I go back to the M&A menu and then go back to communicate with instrument, the HP-IB bus gets hung up again and I have to power cycle.

I have a couple NI-SPY files which may prove of value if your interested.

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Tim

[MichaelChaney]

Hi Tim,

This is not normal behavior for a 488.2 compliant device.  If you could post a Spy capture that shows the calls leading up to the timeout.  I can have a look at the bus status to see what might be causing this.  Also, make sure you can verify this behavior with only one device connected to the bus, just to rule out any conflicting devices.

[Tim Povlick]

Hey Mike,

Attached are two captures.  CAPTURE.SPY shows  the results of M&A looking for instruments on the bus.  It takes about 2 minutes for this search to return the results.

The 2'nd file capture1.sys showsstep 1-13 my software working fine with the PS.   Around step 14, I started M&A.  Step 36 id where a "communicate with Instrument" using an *IDN? a bunch of times in a row without a time out, and step 54 for the 2'nd power supply.  Note: I have to power cycle both supplies when first starting M&A.  This is true with Communicate with Instrument also.  Once talking to an individual PS via the communicate with instrument window they seem to behave fine.

I've tried with only one of the power supplies on the bus and it exhibits the same hang up.


Tim

[MichaelChaney]

Hi Tim,

This is definitely unexpected behavior.  Were you ever able to contact Instek to see if there were any known issues on their end?  Is your application able to work fine with the -HS?  It seems as though this issue is isolated to the Scan for Instruments process.  Keep in mind that it is not always necessary to Scan for Instruments in MAX before addressing a device on the bus, so the temporary work around is to not Scan for Instruments.  I've made R&D aware of this issue.  If this issue is affecting you application as well, please let me know.

[Tim Povlick]

Hey Mike,

I have an email into the Instek support with full details.

Luckily our application doesn't get hung up so this is not a problem at this point.  Thanks for the tip about M&A / scan for instruments as that could prove handy.  We'll leave this as case closed.  If you need me to do any other measurements I am ready to help.

Thanks,

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Tim

[MichaelChaney]

Hi Tim,

I hope you're able to get some good information from Instek.  Just reply to this forum again if you need any more help with this, and I'll do the same if I have any additional information.

Good luck.