Controlling 14 IEEE devices on one bus.

[TheMikey]

I have 14 IEEE devices on the same bus. Every second I will send a 5 character command to each of the devices. Each device shall respond with a 20 byte message. Do you foresee any problems in this?

[AaronK]

Hi,

From your description, you should be just fine. 14 is the maximum number of devices you can have on a single bus, and at that message rate you should be fine. This assumes that the latency of the instruments does not interfere with your plans.

Best Regards,
Aaron K.
Application Engineer
National Instruments

[TheMikey]

Now that poses another question. I thought with IEEE 488.2 you could address up to 30 devices (including the controller). Are you telling me that it actual supports only 14 devices plus one controller? Thanks for the help.

[AaronK]

Hi,
You are correct in both assertions. While you can address up to 30 devices, the published IEEE electrical standard only supports 14 devices + 1 controller where you are required to have 2/3 of your devices powered on.

You can find out more about the standard at the IEEE website. We have info here: http://digital.ni.com/public.nsf/websearch/5286411C990DE2C48525636B005364A5?OpenDocument


There is also more info on IEEE 488 here:
http://zone.ni.com/devzone/conceptd.nsf/2d17d611efb58b22862567a9006ffe76/4dbdf56518f0210c862567c50072bcdc?OpenDocument
Hope this helps out!

Best Regards,
Aaron K.
Application Engineer
National Instruments