GPIB to USB

[Rwdesignsireland]

I am looking for either a ready made device or build information to control a USB device on an existing GPIB bus.

 

[BobK]

There is this nifty tool, called "Google" that can find things like that. You should try it.

Bob

 

[Rwdesignsireland]

Unfortunately google does not differentiate between Gpib to Usb and Usb to Gpib.
I have not found ( in two months of searching) a unit that can act as an instrument on the Gpib side and control an instrument on the Usb side. I am still waiting for a reply on the Pic-plot2 to see if it can do the job.

 

[BobK]

Okay. It helps to tell us what you have done to resolve a problem instead of just asking for help. If you had done that I would not have made my snide remark.

USB -> GPIB makes sense. I am not sure the reverse does. What kind of USB devices to expect your GPIB device to control?

Bob

 

[(*steve*)]

Do you (perhaps) have a device that communicates by USB (so it effectively looks like a serial device)? And you want to interface that to a GP-IB bus?

I can see why you might want to do that. I can also think of a number of reasons why it might be tricky. However, it should be doable.

The question in my mind is how generic could it be? I suspect that it might need to be tweaked for each device and this would kill economies of scale. In the end you'd also need what is effectively a serial to GP-IB device. I think it's probably within the reach of a microcontroller and various support chips. It would be very interesting to see if someone has worked on one.

All of this means that I'd be hitting google, so I'm not a lot of help.

 

[Rwdesignsireland]

OK The full story.
We use MS ExCel to control a number of instruments over a GPIB Bus via an NI USB to GPIB adapter. Data can be sent from any ExCel cell to the any addressable instrument connected to the bus. Likewise data can be received from any addressable instrument and put into any cell.
We now want to include some USB connectable instruments such as Tektronix scopes in our test system. Unfortunately it would be very difficult to modify our ExCel to accommodate the USB ports. It will be very simple to use an addressable GPIB to USB converter like the Tektronix GPIB to USB converter BUT the Tek unit cannot use any address other than 01, therefor only one USB instrument can be connected.

 

[(*steve*)]

Ah, I see.

This device (that you mentioned) does what you need, but the GPIB address is set by the instrument and unfortunately it is fixed as 1, so that limits you to a single device having this limitation.

I can see a couple of solutions. But none are easy:

1. Alter your software to be able to handle USB devices (going forward this might be the best approach)
2. Have multiple GPIB bus devices and place one Tektronics scope on each
3. Create some clever hardware to fit inline with the USB and alter the address that it uses.
4. Create some clever hardware to fit inline with the GPIB bus to alter the address that the converter has.

In terms of hardware (i.e. between 3 and 4), I think that (4) is probably the easiest, but it would take a lot of experimenting and knowledge of GPIB to get it working.

Here (and here) is a description of a USB to GPIB adapter (the opposite of what you need). It links to all the data required to make one. I can see no reason why you couldn't have 2 GPIB interfaces and translate between them, simply changing requests for address 10 to requests for address 1 (for example). [I can't see any reason, but I'm no expert]

As has been noted "there's no hacker demand for these, so they can be quite pricey".