PIL-Box and HP-71b

[salvomic]

(02-02-2018 01:51 PM)J-F Garnier Wrote:  Physically, yes, you can connect the PIL-Box, the 41CX and the 71B in the same loop, for instance without an extra cable:
PIL-Box --> 71B --> 41CX --> return to PIL-Box

From the functional point of view, you must know that the HPIL protocol is driven by one controller (usually a calculator 41/71/75) and one or several devices.
The point is that only ONE controller must be active at a time.
The 71B can release control for other controllers in the loop, and becomes a device, by using the CONTROL OFF command. CONTROL ON puts back the 71B as the active controller.
Unfortunatly, the 41C (as the 75C) can't release control, it is always the loop controller.
So the only operating configuration is: 41CX (as controller), the 71B (as device - using CONTROL OFF) and any other devices (such as the PIL-Box/ILPer system).
To use the 71B as controller, you must disconnect the 41CX from the loop.

J-F

thank you for explanation, J-F, so it is better to control them one at a time... However it is interesting to know how it works.

I wondered that question as I saw some image in which Ilper seemed to send commands (serially) for threee devices, and I thought they was calculators but I was wrong: they are a HP 71, a multimeter and a disk, not two calcs...

However for me it is ok the same: actually I don't want the two calcs exchange data between them but only that computer and PIL-box control one or the other with or without the same loop. Just a curiosity.
My principal goal is to save data from the two HP and then restore if needed, then experiment with printing (in a virtual system). But I'm seeing that with 41CX (always the control) it won't be so easy to have as principal controller ILPer system...
I'll try next week, whit PIL-box.

Salvo