GPIB Discovering 33120A (Keysight Connection Expert 2018) - Page 1
Forum section: electronics / testgear

author: SparkFly
author_rank: Regular Contributor
timestamp: January 26, 2018, 10:26:05 pm
content: Hi all,I have recently picked up an Agilent 33120A which I would like to send some signals I create on a PC. To do this I need to either set up a GPIB or RS232 link between the instrument and a PC. I have downloaded the Keysight Connection Expert 2018 to help me detect if I have set up the connection correctly, but I cannot seem to get the link to work, and I am unsure what I am doing incorrectly.I started by using a USB to Serial converter, ensuring that the 33120A was set to RS232 output and the reciever settings were all matched to the output... No luck. I then tried using a Prologix GPIB to USB converter I have managed to borrow, but again no luck. Finally I used a HP 82350A PCI GPIB card, which is detected by the Connection Expert 2018, but again does not detect the instrument. I have double checked by instrument's address (23) and have tried manually adding the instrument, but the software does not detect it.Is there some step I am missing? My understanding is that once I connect the instrument to PC, it should automatically appear under "My Instruments". Using a much more modern 881x0 series generator at work I have effortlessly managed to connect instrument to PC, albeit with a direct USB connection. Also I have successfully connected my 34465A to the PC, again with a straight USB connection. Is there something about the GPIB or RS232 connection which is different?Many thanks for your time.SF

author: AG7CK
author_rank: Regular Contributor
timestamp: January 26, 2018, 10:59:01 pm
content: No.The RS232 needs a Null Modem cable and (usually) correct handshaking.The GPIB should work out of the box.I have instruments from 1981 till modern boxes connecting via HP / Agilent / Keysight SW in both XP / Win10.You could try IntuiLink or older versions of the I/O - Connection Expert, but I think you should get hold of another instrument with native GPIB connector and get that (successfully) connected via the Prologix first. Comparing with USB gives little information concerning isolating / identifying the reason for your lacking results.

author: TheSteve
author_rank: Unknown
timestamp: January 27, 2018, 12:53:16 am
content: No Keysight software will work with a Prologix adapter.

author: AG7CK
author_rank: Regular Contributor
timestamp: January 27, 2018, 04:13:17 am
content: Id didn't know that, but it seems that the Prologix and IO Libraries might have issues.https://forums.ni.com/t5/Instrument-Control-GPIB-Serial/GBIP-Control-using-prologix-usb-converter/td-p/1841041However, I am and will stay completely ignorant on anything Prologix-related.So OP has to get the Agilent 33120A to work against a different "HP-compatible GBIB card or GPIB-USB adapter" / PC / SW, or get another GPIB instrument to work against the interface he already has in order to narrow down where the fault is.RS232 should however work independent of hardware as long as cabling and handshake are correct.

author: alm
author_rank: Super Contributor
timestamp: January 27, 2018, 10:48:41 am
content: Quote from: AG7CK on January 27, 2018, 04:13:17 amNot so much a HP-compatible GPIB interface, just an interface that supports industry standards like GPIB32.dll (like National Instruments, Tektronix or HP/Agilent/Keysight). The Prologix interfaces were designed as low-cost solutions without any attempt at compatibility with existing software.

author: SparkFly
author_rank: Regular Contributor
timestamp: February 01, 2018, 01:05:00 pm
content: Many thanks for the replies guys. Apologies on my part for the slow response.AG7CK, I'm sure I've tried the RS232 setup correctly... I've used multiple cables, ensured they aren't broken, gone through the every possible setup config and handshaking option with no luck. :/ I think at this stage I'd really like to get the GPIB working, as I have a few older pieces of test gear which only have GPIB. As per your suggestion, I tried linking the GPIB with E3632A and E3631A power supplies, but without any luck. Perhaps this is indicative of something missing in my PC or something I am doing very stupid.TheSteve and alm, thanks for clarifying the issues with the prologix adaptor. I've returned that to my lab, though I'm still having issues when I hook up to a 82350A PCI card.Regarding GPIB, I've tested the cables and they all connect fine. Connection Expert recognises the PCI card, but doesn't autoscan any of the instruments and can't detect them when I try to manually add the instrument.Are there any settings/drivers/etc I could find and present which might help in tracking down my problem? The issue is most likely me... Apologies...Many thanks again for your help and time.

author: Magnum
author_rank: Regular Contributor
timestamp: February 01, 2018, 07:56:21 pm
content: If you use RS232 and the Connection Expert doesn't work try it with a terminal program directly (e.g. Hyperterminal) and send "*IDN?" to the unit. Make sure to use the correct port, baudrate, handshake etc.Edit: Are you sure that the ports of the 332120A are working?

author: ghpicard
author_rank: Contributor
timestamp: February 01, 2018, 10:56:28 pm
content: Quote from: Magnum on February 01, 2018, 07:56:21 pmRegarding to the RS232 connection, I would add that you have to make sure that you are sending a linefeed ( Ctrl+<J> ) to actually get the command be interpreted.Also, you should make sure that the USB-serial adapter is correctly recognized and used by your OS.I have an HP 54616A with the HP 54659A storage/measurement/serial adapter and to be able to connect to it with an USB-Serial adapter I have to use Linux (Xubuntu) as Windows 7 refuses to recognize it as what it is. As linux has no problems at all recognizing it, I ended up installing Xubuntu in a VirtualBox VM and running minicom to do my tests.The next problem I faced was that somehow the linefeed that minicom automatically adds is not recognized by the oscilloscope parser, so I have to resort to use the Ctrl-"J" to get the end of the command recognized.Finally, the parser used in some models is not error tolerant. Meaning that if you make a mistake in the command syntax (remember it is not an editor so backspace is interpreted as an additional character) the parser just hangs and stop listening to the port. In the case of my 54616A, the rest of the functions of the oscilloscope are not affected. This does not happen with my HP 54542A, which gracefully recovers from errors and is ready to let one try again after a couple linefeeds are sent to it.But first of all, make sure your RS-232 interface is working OK and setup to the same comm parameters as the instrument. The safest bet is 9600 baud, DTR control (only if you have a null modem cable between the serial adapter and the instrument, otherwise XON/XOFF). You can test PC interface side by setting XON/XOFF control and tying pins 2 and 3 of the serial connector together and typing on any serial terminal program. In the windows world, Hyperterminal is long gone, but PuTTY has a serial console mode and MobaXTERM has too. In the Linux world, minicom is a safe bet.BTW... what kind of serial connector do you have on the instrument side?Let me know if you need further assistance in trying the RS232 interface and I will probably be able to help you. I have just trodden this trailGaston

author: bitseeker
author_rank: Super Contributor
timestamp: February 02, 2018, 05:01:28 am
content: SparkFly, this may not be the cause of your GPIB issue, but be sure you don't have a GPIB address collision between the USB/PCI controller and any of the devices (33120A, E3631A, etc.) you're trying to communicate with. I think the controller is 21 by default, but double check in the Connection Expert configuration.

author: SparkFly
author_rank: Regular Contributor
timestamp: February 02, 2018, 06:01:24 pm
content: Thanks for your replies again.I have retested with a serial pci card in my desktop and the RS232 link to the 33120A with PuTTY and I have it working.Quite happy about that. It is now also recognised in Connection Expert. Thanks to you guys for helping me with that!And also the GPIB works... I'm quite puzzled by this, as I can't figure out what I've done differently to the previous attempts, so not really much was learned. Ah well. I'm sure there will be plenty of opportunities for it to break in the future.Regards, SF.

author: bitseeker
author_rank: Super Contributor
timestamp: February 04, 2018, 02:19:00 am
content: For GPIB, there is firmware that has to be loaded into the controller. Perhaps it didn't load properly before. In any case, glad it's working. Happy controlling, testing, measuring, etc.