HP-41C HP-IL REMOTE & LOCAL commands

[J-F Garnier]

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.

When the remote/local were used to select between commands and data for interfaces, the same behavior was kept unfortunately.

To make the things even worst:
on the 71, "LOCAL" uses NRE (Not Remote Enable),
but "LOCAL :1" uses GTO (Goto Local) !
(same on the 75).
Your HP71 code should NOT work !

And there is also this LOCAL LOCKOUT command :-)

J-F