Limit Switch Issue

[Yodamadashi]

Hello,

We are currently trying to program our limit switch so that it limits the range of our arm (we have it so that when the arm hits the switch, the arm will be unable to move against the switch).

We have all the logic and programming finished, but the limit switch is always returning a true value. We have checked the wiring many times but the switch always shows up as a true value.

We are opening the DIO and getting the value from the DIO Get, and we tested the switch many many times, and unfortunately it always gives a true value, even if the switch is being pressed or not pressed.

Things we did: Changed Switches, Rewired, Changed Slots, Tested Switch with an indicator and a probe.

The switches were actually working (electrical test), they registered a value of true or false. However, the DIO shows up as always true in the labview reference get.

Any help on debugging this issue would be very helpful!

[Alan Anderson]

Please describe in detail exactly how you have the switch wired. What connections on the switch are going to what connections on the control system?

Can you show a screen capture of the program? It would help to see the relevant parts of both Begin and Teleop.

[Yodamadashi]

I have added the jpg's to the attachments.

The teleop logic right now is missing (we removed it so we can just test the values with a probe/indicator).

I have also linked a picture of the wiring.

[Alan Anderson]

Originally Posted by Yodamadashi

I have also linked a picture of the wiring.

Your wiring is wrong.

The DIO pins have an internal pullup resistor to +5 volts. When nothing is connected, or when your switch is open, the value will be TRUE. When your switch is closed, the value will be...TRUE.

You need to put the switch between the SIG and (-) pins (the white and black wires on a standard PWM extension cable). Do not connect anything to the center +5 pin. That way, when the switch is closed, the SIG pin will be pulled to ground and read FALSE.

[Yodamadashi]

Thank you for your quick reply before shipping out!

We will try it out right now!