Controlling many GPIB's

[terwelu]

Hi there,

I just saw in my labs there are many instruments with GPIB port. I know that I can control and grab the measurement data from that instruments. However, how to control many instruments with GPIB communication simultaneously? In computer networking analogy, I know that I can simply use switch/hub to communicate between the clients/servers. Is there any sort of "switch/hub" that can connect multiple GPIB and control it (e.g. via LabView) ? Do I need to convert all of my GPIB port with GPIB-RS232 or GPIB-Ethernet before I can use the switch ?

Thanks.

Ricki

[Dennis_Knutson]

The 'switch/hub' is the GPIB controller in a pc. You can connect as many as 15 instruments to a single controller. You might want to start by studying this. 

[terwelu]

Hi Dennis,

Correct me if I'm wrong, but when I read it, I got impression that the GPIB controller is built-up on PCI card (or not?).  Well, PCI or not, I prefer to have one cable/connection only between PC and the switch/hub. It's more really like when a server connected with one UTP cable to the switch before it spreads the signals to the clients. I prefer to have a stand-alone switch/hub for GPIB and then some GPIB instruments connected to the switch/hub (not PC). I'm trying to search for that kind of hardware from NI but I keep losing it. Any suggestion Dennis ?

Ricki

[ninlmartijn · Accepted solution]

Hello Ricki,

Thank you for your forum post. The ethernet to GPIB is the only solution for your problem. You are able to connect 14 GPIB devices to one convertor.

Best regards,

[terwelu]

Dank u wel, Martijn ! Yes, that's what I'm looking for !

Groeten/Regards,

Ricki

[Albert.Geven]

Maybe this is what you are looking for but connecting one cable to the first instrument and connecting this instrument to the other instruments is all you need.

So the extra hub is not necessary only adding more problems.

You cannot compare gpib to a hub based system. It is more like the older ethernet systems with coaxial cabling !

Remeber it is a bus not a point to point system.

[terwelu]

Thanks Albert. I really appreciate your information. However, could you be more specific with your statement :

"connecting one cable to the first instrument and connecting this instrument to the other instruments is all you need."

 When you said it is a bus, then your statement is make sense to me.But, on the other hand, Martijn said I can connect up to 14 instruments with one converter.In my perspective, each GPIB instruments will be assigned with one unique ID and so the PC (via the converter) can recognized every single instruments. But this make the configuration as point-to-point, not a bus. 

Hmmm...Martijn and Albert, would you mind to confirm about this configuration ?

Alvast bedankt,

Ricki

[RayFarmer]

Hi,

Try this bit of information on example how GPIB instruments are connected

http://www.hit.bme.hu/~papay/edu/GPIB/tutor.htm

Regards

Ray Farmer

[terwelu]

Hi Ray,

Thanks for the info. Now I know more about GPIB. And I believe both Martijn and Albert are giving the correct answer but in different way of explanation. When I saw this figure 1, I think Albert has this configuration. Meanwhile, Martijn would suggest me to use figure 2.

Figure 1

 

Figure 2

Both configurations need Amphenol or Cinch Series 57 MICRORIBBON or AMP CHAMP type from the computer, or at least use Serial/USB/Ethernet to GPIB converter. In my case, I prefer use common Ethernet communication. In addition, I don't want to use my computer as GPIB controller. Instead, I'll let my switch/hub as GPIB controller. So, I think I should considered both configuration in my proposed system.

Albert, probably I wasn't wise enough to use term "switch/hub" related to UTP or Coaxial cable since everybody knows it can not be the same. My problem was to find the tools/device that can handle or control many GPIB-coimmunication-type instruments. In signals point of view, (I think) it has similarity with switch/hub function in computer network --> The server can identified and give commands or read data from every single client. But you are absolutely right, in physical connection it can't be compared to UTP or coaxial cable configuration. 

Regards,

Ricki

[Dennis_Knutson]

You are still misunderstanding the basics. Your computer is the controller no matter what. The configurations in the image are the same from the pc to the first instrument. All that you are doing with the ethernet device is extending how far away you can place the instruments from the controller. There is a limitation of total GPIB cable length. If that's a concern, use the ethernet solution. Otherwise, it seems like you are just wasting money.