Wiring Diagram check

[cropwell]

The CN1 is the BOB's (CN == "Common 1" or "Input 1" ? + ground).

1. You move your gantry or whatever triggered, or home your machine to be safe and reset Mach3. This releases the triggered switch.

I might be wrong on #4 and #5. I don't understand why you have a 12V buzzer. Doesn't the BOB send 5V through the limits circuit ? Therefore, having a 5V buzzer would be enough ? It seems to me like your diagram causes the BOB to take 12V in when you press the override switch. I'm not sure the BOB can take that much on the input pins (thought I know it can on the spindle control interface).

Now if you look at my diagram, it acts similarly to yours, I think :/ ? When a limit is triggers, it opens the circuit and you have to put the override switch in position 2, which closes the buzzer circuit. The buzzer is now powered with the BOB 5V (unless I'm wrong about the BOB sending 5V through those pins).

Hi,

My connector CN1 is just there to show the connection point to the BoB.

Do not try and power anything from the BoB input terminals. They may be at 5v due to internal pull-up resistors, but they will not supply enough current and you may damage the BoB. Likewise the output terminal should not feed any circuit with any power demand greater than a relay.

The buzzer can be any small DC buzzer, just feed the +ve side from an appropriate power supply, 5 or 12v depending on your buzzer. I just happened to have a couple in a drawer.

As Clive said my warning buzzer is a separate side of the switch. On my machine I separate ++ limits from -- limits so I use a 3pole double throw switch to override both inputs and also earth the buzzer.

Don't try and Home the machine when a limit is being overridden. You may be the wrong side of the Home switch and your machine will try to keep going in the wrong direction.

Before you connect Home and Limits to the BoB, verify they are correctly wired using a test meter. BoBs are fragile little buggers, so treat them well.

Why are you using a relay for Limits switching ? It only adds more to go wrong ! What would happen if your 24v power failed and you didn't notice.

Cheers,

Rob