prop1 help

[mechanikins]

hi there,

i've just started using the prop1 i bought 3 or 4 years ago and it was working great until all of the sudden it is giving me problems.

i'm using pin6 for the trigger input and i'm connected to outputs0, 1, 2 and 3.  all of the sudden there is no voltage for output2.  i thought maybe i shorted something and blew the ULN chip so i replaced it but i still get the same result.  i've tried moving to one of the other spare outputs - 4, 5 and 7 but i get no voltage out on any of those,  but output 0, 1, 3 and pin6 still seems to be just fine???   any ideas?  is the STAMP shot?

[menehune]

A few more details about your setup would be helpful.

What do you have hooked up to the outputs?  Lights, motors, LEDs? 
You are using the Outx screw terminals, not the three pin connectors?

I believe the ULN is actually switching the ground, not supplying a voltage to the load, so placing a volt meter between the Outx and GND terminals will not show a voltage.

[mechanikins]

i have 24vdc valves connected to the output terminal.  i am checking voltage by putting my meter across the V and output pin on the terminal block.  i see the voltage on output 0, 1 and 3 but no voltage on output 2, 4 ,5 or 7.  i didn' try 6 since i'm using it for trigger input and it is working fine.

[mechanikins]

oh yeah - i do have 24 vdc relay connected as well.

actual setup is

output 0 and 1 = 24vdc valve
output 2 and 3 connect to 24vdc relay

[JonnyMac]

Do you have a Prop-1 Trainer?  You can use that to see if the I/O pins P0 - P5 are in fact working (make the pin HIGH and the corresponding LED will light, and the OUTx terminal should go to ground).

[mechanikins]

i don't have the trainer.  can i just connect an LED to the pins?  would it be RB?

[JonnyMac]

If you want to mimic the trainer connect an LED like this:

Px.W  -----[470]----|>|----- Px.B

Use a 470 ohm resistor to limit the current through the LED and protect the PIC interpreter.

[tnb720]

hey johnnymac
iam having the same problem, but i have the prop trainer and it shows outputs working correctly.  i also tried replacing the ULN chip. i used a 24vdc mac valve connected to out0. does not work. ive tried other outputs as well.i am using a good 24vdc pwr sply, but i tried removing that one and using just your pwr source-still no good.  any advice. thanks tim

[JonnyMac]

1) Make sure the power switch is in the P2 position and that the V+ LED is lit
2) Test the valve by connecting one lead to V+ and touching the other to the GND terminal
    -- when you touch the GND terminal the valve should operate
3) Check the orientation of the ULN; a few customers have installed them upside-down