Simple PhotoCell Timing System
(S.P.T.S.)
TROUBLE SHOOTING GUIDE
(c) Bryan Brown & Art McEwen 1997-1999
All rights reserved, not to be copied without permission.
Problem - No response in CHITI (or other SMI programs) from sensors
- make sure the DB25 connector is plugged into an LPT port
- check the LPT port address to ensure that the operating system is using H378 or H278 or H3BC. You can use the DOS command "MSD" for this or find it by using CHITI.EXE
- double check your wiring to see that you have connected to the right pins/sockets
- all SMI programs except CHITI need to have the correct port identifier set in PARM.TXT in order to funtion properly. CHITI looks at all three ports.
- if all else fails, you may need to adjust the resistances of your PCells to match the "Trigger Point" of your port. Review the "Trigger Points" section
and the "Changing PCell Resistances" section,
to make sure that your PCells are compatible with the "Trigger Point" of your port/pin.
Problem - Program Termination Error Messages in ENZO (also MONTY/LEMANS etc.)
- "Invalid Path - Can't find C:\SCUDM directory"
You must create a directory call SCUDM on your C: drive
- "Can't find PARM.TXT in C:\SCUDM"
Store the downloaded parameter file in the Scuderia McEwen directory
- "Check Edits in C:\SCUDM\PARM.TXT"
One or more of your parameters is wrong. Display the contents of PARM.TXT to see the valid values for each field. Only the first record is used in the programs, the other records are just for your reference.
Problem - Errant signals detected (laps counted when no car near sensor)
- source light too dark
- move light closer or get brighter light
- move PhotoCell closer to light source
- Minimum Lap Time in PARM.TXT may be too small
- possible electrical interference, use
shielded cable
Problem - Missed signals (car goes over sensor but signal not detected)
- source light too bright
- move light further away or get a less bright light
- move PhotoCell further away from source light
- Minimum Lap Time in PARM.TXT may be too large
- the sensitivity of your PCells may need some tuning, particularly with
very fast (and short) HO scale cars. A resistor may be needed to increase sensitivity, see the "Trigger Points" PhotoCell Sensitivity section.
Problem - Same PCell works fine on one lane but won't work on the other
...or... I can only get one lane working
- Your "Trigger Points" are likely significantly different from lane to lane.
You are probably using a relatively new computer.
Your PCells are out of range with the Trigger Point of the port/pin.
Review the "Trigger Points" Trouble Shooting section and
the "Changing PCell Resistances" section.
You probably need a resistor or a new PCell.
Don't worry, we can solve this problem!
Problem - My wife thinks I'm crazy to be playing with toy cars.
- try flowers & chocolate first
- as a last resort, dinner & dancing (ugh)
Last Updated July 21/2001
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