Well, tonight has been an interesting one. The last electrical thing I have to get working is our pneumatic system, and one day to do it, uhhg.
Anyways, I have been trying to get the compressor to run, but I can’t get it to do that. The wiring is as follows.
Power cables from Distribution board to the Spike, and the other M+ and M- Terminals to the compressor.
PWM cable running from spike to the Digital Sidecar Relay channel 1. The Black wire of the cable is closest to the edge/outside of the digital sidecar, and is innermost on the Spike.
2 pin cable, whose connector was cut off and wires stripped to be hooked up to the pressure sensor. The intact 2-pin connector is connected to the middle and outside pins on the Digital Sidecar on the I/O. This is where I think we might be wrong. Do we need to use another 3-pin PWM cable, and run the wiring to the outermost pins on either side of the digital sidecar, not connecting to the middle one?
Simple put, do we connect the pressure sensor wires to the (-) and Signal pins on the digital sidecar, and NOT the PWR pin?
Like I said the above #3 is where I think our problem lies. I’d like to try it, but I’m at home now.
Now, I haven’t even tried to conect the solenoid yet. We will be using the Festo one, because it is the only one we have. I know you hookup wires to 1 and 2 on the solenoid, but what pins do they connect to on the actual Pneumatics Bumper on the CRIO? And I assume we need to cut one end of the PWM cable to do the connection on the solenoid right?
This is our first year of doing anything robotics at our school, and we just started 2 weeks ago because of delays. I have already learned soo much from reading these boards!
anyway, your wiring seems correct. if you look at the pwm wires that you are sticking into the DIO pins, (assuming they are the right direction) the signal is the white wire, and the power is the red wire. iirc, both of those wires have to go to the pressure sensor.
since you didnt mention anything about the programming actually asking the compressor to work, im going to assume thats most likely where the problem lies.
your assumption is also correct for the festo valve.
I’ve been using really simple compressor labview code that I’ve seen on some other threads.
It’s really odd, because when I disconnect the PWM cable from the DIO the compressor turns on for a split second. And if I keep it REALLY loose on the pins, like holding it barely on the pins, the compressor will keep running, but the PWM cable gets REALLY hot. The PWM cable I’m referring to is the one for the pressure sensor, not the relay/spike.
The pins I am connecting it too are the PWR and (-) pins, which are the middle, and outermost/closest to the edge pins. if you have the 3 pins like this " " " we are hooking the wires here " 0 0 the 0s representing our connections. This is viewed as the parallel port being at the top, and the RSL at the bottom.
I read in another post the it should be hooked up like 0 " 0 but I have no idea.
ohhh
um you need to have the power and signal pins hooked up to the sensor, otherwise whats reading the signal? the ground? certainly you wouldnt want that
and normally when something gets really hot thats a sign that you shouldn’t be doing it. my guess is you are either arcing it or giving it an area of high resistance due to the small contact area.
you might also want to put a ohmmeter to the sensor to see if its still working after the various “tests” you put it through. ime its pretty durable, but you never know.
in past years i remember the pwm connector having the wires at the oppisite side of the molex thingy connected, like 0"0 (in your diagram).
all i can say now is ohm it out to verify that the sensor is working, and double check the code (you shouldnt prematurely stop the compressor; that would be bad. its one of those open-start-forget sort of things)
In the code I have seen two different examples on these forums. Now I don’t really understand LabView very well yet.
But I have seen an example with the Open and Start outside of the while loop, and another example where Open is outside the while loop but Start is inside the while loop. Which is correct? I would assume the first one is correct, but I don’t know.
ok, i just verified that the pressure switch goes to ground and signal on dio’s.
anyway, we dont have a compressor on our robot, but i think at some point we tested code with it. I remember opening and starting the compressor outside of the main loop, then sending the wire through the main loop, and stopping and closing it on the other side of the loop. that should make it continually run while the bot is on.
Alright, that PWM configuration is the only one we haven’t tried, because we were using a 2 pin connector, which makes it impossible. When I get there tomorrow I’ll rewire with a 3 pin connector and wire it in that fashion. Hopefully that will solve our problem.
Oh and for the solenoid, when we get to it, which pins are connected on the pneumatics bumper on the cRIO? Since only 2 wires are used, and 3 pins are available, I haven’t a clue, or at least not yet.
Burt,
By now you know that the pressure switch should not be connected to the + volt center pin. The two wire pin was intended for another purpose. The simplest method is to use a PWM cvable, cut off one end, insulate the center pin with heatshrink or tape, and connect the other pins to the pressure switch. The pneumatic manual on the FiRST website should answer most of the remaining questions.
Alright we are going to do that, but what about the actual solenoid for our actuator? Only 2 pins are used out of the 4 on the festo valve, but there are 3 pins on the pneumatics bumper. So which pins are connected to the festo valve?
Look again. The Solenoid Breakout should have two rows of pins, not three. The pin closer to the circuit board is ground (-); the other one is the drive (+) signal.
hey all,
sorry if this seems a little awkward, but we seem to have lost our directions for connecting the solenoid. could someone give me an overview, in stupid mans terms, please?
