HP-41C HP-IL REMOTE & LOCAL commands

[Garth Wilson]

(06-03-2018 08:32 PM)J-F Garnier Wrote:  Hello Sylvain,

Yes it was a common pitfall at the time.
The HP41 with the HPIL module only is unable to set the parameters of the HP82164, and also of the HP82165/166 GPIOs (that requires the use of DDL/DDT commands).
The extended I/O module was mandatory with these interfaces -unless using the default configuration.

I believe the behavior of the REMOTE/LOCAL commands has an historical explanation.
They comes from the HP-IB (aka IEEE488) world in instrumentation applications, and intended to enable or disable the remote control of the instrument from a computer rather than from the front panel. Once the instrument remote commands were enabled, it was possible to temporary go back to local (front panel commands) until a new command is received.

That's probably why I never had any trouble with it. My original purpose for getting the 41 and HP-IL in 1986 was to control IEEE-488 equipment on the workbench through the HP82169A HPIL-to-HPIB interface converter. The equipment consisted of things like signal generators, DMMs, and relay units, and they mostly had their own front-panel controls, so they could be used manually without external computer control, or under computer control for automated test setups. During program development, I might occasionally want to press the LOCAL button on one piece of equipment or another to check something by changing settings from the equipment's own front panel. I always used the 41 in MANIO (manual I/O address selection), because the HPIL-to-HPIB interface converter, although mostly transparent, did not have the autoaddressing like HP-IL does; so each piece of equipment on the IEEE-488 (HP-IB) had to be addressed with SELECT. There was no choice about that; and all of their addresses had to be above the number of things on HP-IL, and the interface converter had to be the last thing on the loop. Printer, mass storage, and anything else I had must come before the HP82196A.

I have the FSI164A which was almost identical to the HP82164A except that it came with two RS-232 channels standard, and up to eight if you paid extra, and could be powered with batteries. I originally used it to control an EPROM programmer, and later, interfaced to other things on the workbench. I don't remember ever having any problem with it, although I heard it has a bug with even parity (which I never tried).

Sylvain, I do find it a bit curious that you would use AUTOIO and then 1 SELECT.