PDPRP Technical Debugging Tips
PDPRP Technical Debugging Tips
These are just some last-minute ideas that might be useful in
solving problems that I've seen before.
LBC does not flip any mirrors
The side-effect of this will
be the constant production of LBA not returned errors. First, make
sure the hardware Lightbeam Controller works- 99 a couple benches and
see that it moves. If not, that's your problem. Also, make sure the
computer-control switches on the hardware Lightbeam Controller panel
are engaged. Now, if all those tests pass, quit LBC and re-start it
from the Unix command line (lbc). I don't know why, but
this often solves the problem. I don't know if it is a logic bug in
the code, or something weird with addressing the Digital I/O card that
needs to be reset. If this happens continuously, perhaps we can build-in
a Digital I/O board reset command in LBC.
Telpos does not respond
That is, Telpos is not giving new positions
and the Quit button has no effect and doesn't even highlight when the
mouse is placed over it. The only time ANY of the software hangs up
without giving the user notice (I think) is when it can't get access
to the serial port. So, in this case, make sure the serial connection
is made (use kermit from the Unix command line, not
the pcg command in Telcon, as this will not work as well,
probably, if Telpos is not working) and all the cables are fine. If this
all looks ok, run hqtest.tcl. This program is in
~obs/pdprp in Ingrid and can be run with the following command:
wish hqtest.tcl. In there, click Get it
next to the Sport busy section. The returned value will probably be 1, although
it should be 0. Set it to 0, by entering 0 in the entry box and clicking on
Set it. Somehow, Telpos probably got stopped after it
had told HQ the serial port was busy, and before it told HQ the port was
available again. Thus, when Telpos was re-started, it couldn't send a command
and was waiting for the serial port to be free again. Unless a program
is terminated while it sets this flag, but before it clears it, and if it
is re-started without having re-start HQ, this error condition should never
arise. If it does, however, we might want to add a time-out loop while waiting
for the serial port to become available.
Problems communicating to other Host Computers
As mentioned above,
I think the only time the program will become inactive without popping up
some error box is if it is stalled in a serial port communication routine.
So, check the serial connections on both ends and see if that's the problem.
Return to PDPRP Technical
Info Page
Return toPDPRP Main Page.