topic Re: GPIB communication issues between PC and device in Instrument Control (GPIB, Serial, VISA, IVI)

GPIB communication issues between PC and device

jonathan27 — Fri, 10 Nov 2017 09:57:45 GMT

Hi ,

I have a device, which has an older GPIB version(it is DOS95 base I think). And I want to hook it up to a WINDOWSXP PC which has an updated version of GPIB, but whenever I do it, the WINDOWS XP can't detect the device.

The device, can run on an old DOS based computer. I tried connecting to the device in parallel (using the windows XP PC), so I could check what GPIB commands trhe device is throwing(using NI SPY). But whenever I do that the device wont communicate. However, when I remove the parallel connection to the Windows XP, the device can communicate again.

Can you help me on this?

Thanks!
Appreciate your help

Re: GPIB communication issues between PC and device

Albert.Geven — Fri, 10 Nov 2017 10:16:05 GMT

What is the device and what does the program do?

Re: GPIB communication issues between PC and device

jonathan27 — Fri, 10 Nov 2017 10:24:38 GMT

Well,it is like a machine that acts based on GPIB commands from host.

I.E.

Do task A => GPIB command1

Do task B => GPIB command2

and so on...

Yeah, I know it is a little vague, but I think this should be good enough.

Though before they start, they have some sort of handshake.

I know the device GPIB is old because the device hardware is old, just want it to communicate with my newer PC.

Thanks!

Re: GPIB communication issues between PC and device

njacacia — Fri, 10 Nov 2017 14:24:01 GMT

@jonathan27 wrote:

Well,it is like a machine that acts based on GPIB commands from host.

I.E.

Do task A => GPIB command1

Do task B => GPIB command2

and so on...

Yeah, I know it is a little vague, but I think this should be good enough.

Gee. You think that is good enough? ? ?

Re: GPIB communication issues between PC and device

jonathan27 — Fri, 10 Nov 2017 14:49:09 GMT

:D, you are a bit harsh...that is all I can give you. Generally the problem is if I can communicate my old hardware with an old GPIB using a new one.

There is a reason why I can't give you a detailed explanation of the hardware I am using. Hope you can understand.

Re: GPIB communication issues between PC and device

Minions — Fri, 10 Nov 2017 14:55:08 GMT

As this sounds like an older piece of equipment, you might try the following:

https://forums.ni.com/t5/Instrument-Control-GPIB-Serial/What-is-the-Scan-for-Instruments-sequence-for-a-GPIB-USB-HS/m-p/3644928#M75093

Re: GPIB communication issues between PC and device

jonathan27 — Fri, 10 Nov 2017 15:39:44 GMT

Base on the link:

I should poll on addresses (I think it is 0-30), then if my host find my device let us say, in primary address 6...it will then send an IDN query? or query that asks what device it is?

Does this mean the moment my device responds to that query, then I can now communicate? (so if device does not respond to this query, then device will not communicate? Is this some sort of flag?)

I understand there are legacy devices that does not respond to IDN query.

Thanks!

Re: GPIB communication issues between PC and device

njacacia — Fri, 10 Nov 2017 16:13:18 GMT

@jonathan27 wrote:

There is a reason why I can't give you a detailed explanation of the hardware I am using. Hope you can understand.

Hope you understand then that there won't be a detailed answer.

Re: GPIB communication issues between PC and device

Minions — Fri, 10 Nov 2017 16:35:28 GMT

If you know the gpib address, then send one of those requests at a time. Your device should respond to one of those (Unless it uses an encoded system).

Re: GPIB communication issues between PC and device

jonathan27 — Sun, 12 Nov 2017 12:51:32 GMT

I'll try that, what do you mean by encoded system?

I tried attaching a GPIB cable hook on an Windows XP PC (in parallel with the old system).

The problem is whenever, I do that the communication between the two system (device and the old host PC) is lost. Able to communicate again when I remove the cable not sure what would cause that, so am unable to do a NISPY between the old system to be able to see the commands they are throwing to each other.

Would this be any hardware incompatibility issue? Since the old system is running on an old OS, I think windows98? (and my PC is running in XP?)

Re: GPIB communication issues between PC and device

Minions — Mon, 13 Nov 2017 14:12:47 GMT

You can have two controllers tied together except that they both cannot be at the same GPIB address. By default, the controller is given GPIB address 0. The other choice is to configure the second controller as a listener prior to connecting it to the bus.

Re: GPIB communication issues between PC and device

JÞB — Mon, 13 Nov 2017 21:19:03 GMT

@Minions wrote:

You can have two controllers tied together except that they both cannot be at the same GPIB address. By default, the controller is given GPIB address 0. The other choice is to configure the second controller as a listener prior to connecting it to the bus.

And, of course there can only be one CIC (Controller in charge) Both controllers would be defaulted as the CIC and therefore each would prevent the other from actually controlling the communications on the bus.

So, Go read up on GPIB Start with a Google search of IEEE-488 (Or read any Hewlett-Packard, Agilent or Keysight manual) then STOP just hooking things up wrong and expecting them to work right.

Next Read the Manual for your device. (Or at least tell us what it is and likely we will read the manual for you and even point out what you are doing wrong)

PEBKAC

Re: GPIB communication issues between PC and device

jonathan27 — Tue, 14 Nov 2017 13:01:10 GMT

Ok, so that is the reason. I get it now I need to set my listener to different primary address (PAD) correct?I'll try that one.

Thanks!

Re: GPIB communication issues between PC and device

jonathan27 — Tue, 14 Nov 2017 13:06:54 GMT

Thanks, yeah I've been reading the GPIB manual and been lurking on the forums. I'll try what minions suggested.

I don't have the device manual, and it is not something you can google. That is why I'm planning to hook a PC as a listener, with the communicating device.

I'm trying to contact vendor for the manual though, this is a pretty old and bulky equipment 😄

Thanks!

Re: GPIB communication issues between PC and device

jonathan27 — Wed, 22 Nov 2017 07:05:38 GMT

Device already communicated, hooking another GPIB device in parallel helped it communicate with my PC.

(once it responded on my IDN query, everything went smooth)

Not sure why, though.

Thanks for your help guys!

Re: GPIB communication issues between PC and device

JÞB — Tue, 28 Nov 2017 13:18:15 GMT

@jonathan27 wrote:

Device already communicated, hooking another GPIB device in parallel helped it communicate with my PC.

(once it responded on my IDN query, everything went smooth)

Not sure why, though.

Thanks for your help guys!

If addind another device to the bus fixed the communications the hardware drivers for the handshaking lines are under designed or faulty.

Re: GPIB communication issues between PC and device

jonathan27 — Fri, 01 Dec 2017 10:53:02 GMT

Hi Jeff,

Can you help elaborate? I can't just accept in my side that it just worked by doing that there has to be a logical explanation haha.

How can adding something in parallel fix a faulty driver?

Thanks!
Marcus

Re: GPIB communication issues between PC and device

AnalogKid2DigitalMan — Fri, 01 Dec 2017 14:26:45 GMT

Did you piggyback the GPIB cable to the 2nd instrument on top of the existing cable at the 1st instrument?

Perhaps the cable to the 1st instrument had an intermittent connection? Try removing and reinstalling all cables to make sure they are seated properly and tightened.

Sea Story:

In one of our labs someone purchased several inferior coax cables. An engineer spent over a day trying to troubleshoot a circuit with an o'scope, he could not figure out why the signal of interest was not at full amplitude. Turns out the BNC's of the cables over time had developed a layer of oxidation preventing a good connection.I swapped out the cable out with a good one solved the issue, then immediate threw out all of the junk ones.

-AK2DM

Re: GPIB communication issues between PC and device

JÞB — Sun, 03 Dec 2017 15:23:08 GMT

If the device meets IEEE 488 standard, no trouble!

If the device is poorly designed.... You need a compliant device to hold the handshake lines in an appropriate state.

Google your heart out.

Re: GPIB communication issues between PC and device

jonathan27 — Mon, 04 Dec 2017 03:44:25 GMT

Hi AnalogKid2DigitalMan,

If piggyback means in parallel yes, I was thinking maybe we have some issue with the GPIB port itself of the primary (1st) instrument. And connecting the second instrument in parallel seem to fix it...somehow.

Thanks for the inputs! I'll put that one on my watchlist whenever I would have a problem in GPIB communication again.