On 2025-03-22 10:11 PM, Radu Bogdan Dicher via groups.io wrote:
If I understand correctly, you're saying that the # GPIB connection may
"port" another, "hot swapped" instrument to the same # GPIB?
GPIB doesn't have the concept of a "connection". Each device sets its own address, sometimes via DIP switches, sometimes, via front panel commands, etc., but that instrument "knows" its own address. It's up to the user to ensure there are no collisions. There are 31 available addresses - often set by 5 DIP switches. The 32nd address is reserved as described below. The whole concept is quite different from either USB or Ethernet addressing.
To start a data transfer (which may be a command, or some sort of data), the Controller (usually a PC adapter of some sort these days; could be an internal board with special drivers, or external like my KISS-488) issues a command to one address (maybe even itself) to become the Talker, and to one or more devices (instruments) to become a Listener. The talker then proceeds to send bytes, ending with a specified termination condition. The Controller usually then turns the bus around, addressing e.g. the instrument to become Talker, and e.g. itself as Listener, and data flows the other way. at the end, it issues Untalk and Unlisten commands (that 32nd address).
I include a fairly detailed discussion of GPIB concepts in the beginning of the manual for my KISS-488, which you can download freely at
Steve Hendrix
