Loc() with PB3.5 and PBVision

[Mike Burgett]

I am converting an older program written in PB3.2 to PB3.5 and
PBVision. I am communicating with a Jaguar Scale Unit via Serial
Port COM1. To describe my process, I send a "P" to the scales and
it send back a String containing the current weight. The function
is needed to make sure that a response is received from the scales.
This function works fine under PB3.2 but just appears to stall out
when compiled under PB3.5 and PBVision. The program hangs (or never
leaves) the DO:LOOP routine. This code did work until updated. I
removed the LOC code and utilized just a .15 second delay and then
read the port and thats fine. But I still need to have some way to
know when to resend the "P" so the main program does not hang. Is
LOC the problem here?

FUNCTION ReadWt 'send a 'p' to the scale and it will send back
ST=TIMER
PRINT #3,"P";
DO
IF LOC(3) > 5 THEN EXIT DO ' Exit Do when something comes in from port
IF TIMER > ST+0.5 THEN
PRINT #3, "P"; ' IF TIMER TIMES OUT THEN SEND ANOTHER P
ST = TIMER
ITERATE
END IF
LOOP
INPUT #3,X$
ReadWt = VAL(MID$(X$,9,7)) - zeromv
END FUNCTION

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Michael Burgett

[Tom Hanlin]

LOC is fine. Make sure your serial cables are firmly attached and,
don't forget to check ERR, especially after opening the COM port.

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Tom Hanlin
PowerBASIC Staff

[Mike Burgett]

Tom,

Thanks for the reply. I have other code elsewhere in the program
that I tried when this routine fails. So I can confirm that the port
is opened and that communications are possible. Like I described above,
I can send the command "P" out the serial port then DELAY .15 then
INPUT #3, dummy$. And that works. But the program hangs when I attempt
to wait until there is something in the buffer. The same code works
in PB3.2 without vision. Hmmmmmmmm


Thanks

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Michael Burgett

[Tom Hanlin]

PB/DOS 3.5 has been out for more than five years now and is often
used for telecommunications work. There are no known problems with
the comm handling. Odds are, there's something that's changed in
your code.

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Tom Hanlin
PowerBASIC Staff

[Kerry Holmberg]

Delay seems to suspend com port processing
Instead of using Delay .15, make a Sub as follows then call it instead of using the Delay.

Sub ComDelay
Etime=Timer+.15
Do
If Timer>=Etime then Exit Sub
Loop
End Sub

Note that there is one problem with this, If the Etime value goes over 86400 (when the timer recycles to 0 at midnight) the value of Etime will never be reached and the loop wil never exit. There are ways to work around this but thats a whole other program, this should get you past your current problem.




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