E-stop Working

The E-stop now works, but I had to make a few modifications:

I had to bypass the IRC5 e-stop input. I couldn’t figure out how to get an e-stop output from the IRC5 without setting up I/O in my RAPID program, and I didn’t want to deal with it. The e-stop going IN to the IRC5 works perfectly.

I had to add level-shifting to the 5V input from the cRIO so that it would go into the xBee modem as ~3.3V. I accomplished this by putting a 10k resistor in series with the input and then a signal diode from the I/O pin to the 3.3v rail.

The LM317 voltage regulator gets pretty warm, but isn’t overheating or losing regulation. In future revisions, I need to change the footprint so I can solder it to the board for better heat spreading.

I’ve successfully turned the solenoid relay on and off, and tested all of the inputs to the e-stop. One problem I’ve found is that shutting off the remote has about a 1-2 second lag before the robot will e-stop. I can probably fix this by changing the timeout on the receiver. I’ve also found that when the remote is shut off, it takes about 3-5 seconds for the e-stop to reset. In a future revision, I will use the second throw of the switch to connect a pulldown on the power rail when the remote is in the off state so that it dumps the capacitor faster and resets more quickly.

Other planned revisions:

• Use a better/larger switch (toggle?) for the on/off on the remote
• Polarity protection diodes on all inputs (both remote and receiver)
• Power LED on remote
• Power and Status LEDs on receiver
• Fix footprint issues
• Move xBee on receiver to make it fit in the case better
• Rearrange parts on remote so that it can be mounted to the top of the enclosure and the LEDs don't need holders
• Add a switching regulator to the remote for longer battery life (?) and voltage conditioning
• Override jumpers on all inputs on the receiver.
• Switch to 0804 or through hole resistors