How to HP-71B and HP-41CX via HP-IL?


I connect HP-71B, HP-41CX and HP-82161A cassete to HP-IL loop.

When execute on HP-41CX:

2 XEQ SELECT - select HP-82161A drive


directory readed from tape and listed on screen

When execute on HP-71B:


i receve error message: HPIL ERR: Invalid mode

How to read on HP-71B data from HP-82161A simultaneously connected to HP-41CX?


IIRC the HP41CX is always in Controller mode yet a HP-IL loop can have only one controller. So the HP71 is not a controller and hence can not get the directory.

Check if you can get the dir from the 71b if you turn off the 41cx. Also, check the HP-IL docu of the 71b and see if there is a command to make the 71b the controller and see if you can successfully execute that command.

However my HP-IL knowledge is very limited...



Edited: 19 Feb 2009, 12:05 a.m.


I tried with HP-41CX power off - no luck.

On HP-71B i tried CONTROL ON - error: HPIL ERR:Loop Broken


To use an HP-41 and an HP-71B at the same time in the same HP Interface Loop,

the HP-71B has to be in device mode: CONTROL OFF.

To have the HP-71B to be the HP-IL controller again you have to remove the HP-41 from the loop.

It's not sufficient to turn the HP-41 off, since the loop is broken, as you experienced...

To reset the HP-IL state after removal of the HP-41 from the loop,

perform RESET HPIL on the HP-71B. The loop must be closed, of course;-)



Raymond, what is the difference between:




Can you explain these in some more detail?


I cannot remove HP-41 from loop bacause i have only one HP-IL cable.


You will have to take the 41 off the loop to allow the 71B to access the loop. The 71B can talk to the 41 when in CONTROL OFF mode thru ENTER or OUTPUT commands. It's some time ago that I've last played around with these but someone else might chime in here and provide a better explanation.

A question to the experts: Would it be possible to write an MCODE function to make the 41 give up control of the loop? Or is this hard coded into the HP-IL module and cannot be worked around?


This MCode exists in the HP-IL "Devil" (Developement Module), try function MONITOR. This is the only way I know to use the HP41 in an IL-Loop _not_ as controler.



Thanks for the hint!

I flashed HP-IL Devel, HP-IL Diagnostic, Extended IL, Extended IO rom images to NoV64, inserted NoV64 to HP-41, XEQ MONITOR but MONITOR dont help.
SCOPE function helped, it switched HP-41 from controller to observer mode.

After execute CONTROL ON on HP-71B i readed directory from tape and saved my program on tape - all ok.

But there is one little trouble - all HP-IL commands are executed very slowly, as their intercepts and displays the HP-41.

Edited: 19 Feb 2009, 7:55 a.m.

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