View Full Version : Prox Switches

10-17-2007, 08:12 PM
The Prox switches work some times and not at others. I checked the wires and they are installed right. If I run the X down the table with the arrow keys and then, use the keys to go back it does not stop when the lite goes out, and when past comes back on.


Gary Campbell
10-17-2007, 11:03 PM
Make sure of the air gap between the sensor head and the bolt head. Also.. I am not sure that the software will stop the movement when using the keyboard. What would be important for testing using the keyboard, is that you have a working switch, that is, the light in the switch going on and off and the indicator on the control software indicating that the prox switch is working properly.

10-18-2007, 06:43 AM

"it does not stop when the light goes out, and when past comes back on."

I'm not sure what you meant but the way it should work is when moving toward the prox switch the light should not be on. When you reach the prox switch the light will illuminate and the tool will stop. Once the tool stops all you need to do is release the left key you where holding down and press the right key to move off the prox switch. If you release and press the same key you will move past the prox switch toward your mechanical stops.

Bill Thorpe
10-18-2007, 09:48 AM
Frank, It sounds like you are talking about the PRT. On the PRS the Prox switch indicators are on all the time until it passes over the target then the lamp turns off.

Jimmy, When you find the solution to your problem please post it here. I too have experienced this on occasion.

10-18-2007, 10:15 AM
I have an PRT Alpha upgrade and I find the Keyboard arrows allow me to go back and forth over the prox switches. I think it is supposed to work this way, and only command moves will stop at prox switches. Maybe I have a problem and don't know it!

10-18-2007, 11:25 AM

it appear you have normally closed proximity switches; they're always on until a target trigger it.

When you use the Keyboard control, if your switches are inside the limit of the table (VL command values) you will eventually "hit" a switch as they act limit under normal circumstances. Once a limit switch is "hit" in K mode, it can be override if you attempt again in the same direction.

If you'd prefer to not be able to got beyond the limit location, you need to set the VL values according to this. When File limit checking is on (SF,1), the tool wont go beyond the VL values no matter what... limit switch triggered or not... as long as the table base coordinates are correctly set.

I hope that make sense...

10-19-2007, 05:48 AM
OK, If I understand this right, if, I type in MX -1 and the X is at +1 it should stop at the proximity switch and then I must enter another command to get to -1, is that right?

10-19-2007, 12:10 PM
I don't know if my prox switches are "normaly closed", but the light shows only when they are over the trigger bolts. I am happy with the way my K mode works, allowing me to go to the end if I wish.

My Zero X,Y,command works just fine, so I know my limit switches are working as they are supposed to. Thanks for your comment

03-27-2009, 01:41 PM
Someone can send my the prox switches diagram conecction, i miss mine, thanks a lot.

04-04-2009, 03:55 AM
It appears I got a newer style of proximity switch with my PRSstandard (shipped the end of Jan). It does not have a barrel or the two nuts. The manual has not been updated to address this new style, anyone know how to mount these? Also the bearing on the Y axis have been updated, its now an allen head and no washer. Shopbot should really keep their manuals more up to date.

04-05-2009, 04:54 AM
Here are photos of the proximity switch, any ideas how to mount this?





Gary Campbell
04-05-2009, 08:16 AM
That is the wiring harness for the prox... you are missing the actual switch... the barrrel with the 2 nuts. Email SB tech support

09-08-2009, 02:34 PM
I have the same switches as Gary shows in his photos. Can anyone tell me if they are supposed to light up as the previous model switches do, per the manual? Also, how can I tell if they work or not?


01-23-2010, 06:33 PM
I have the new new PRS Standard control board. According to the diagram they sent, I should have a +12 volt location to hook up into. I don't. Does anyone have a picture of the new set-up, wiring diagram, you can show me? It would help out a lot. Thanks.

Gary Campbell
01-23-2010, 06:43 PM
Do you have the All aluminum RBK box? And if so, what are you trying to hook up?

01-24-2010, 10:26 AM

I do have the all aluminum control box. I was told it has only been out for a few months. I need to hook up the proximity switches and I cannot find the 24 volt connection that I need. Thanks for the help.


Gary Campbell
01-24-2010, 10:47 AM
Good, you first said 12V and that would have been the older model, not the RBK.

Here is a shot of the board as I saw them earlier this year. Note that the +24V is just to the left of the GND and other Prox connections


01-24-2010, 12:12 PM
Looking at the great picture Gary posted you connect prox switches to an RBK using the following connections. I'm not sure what colors you have in your cables so I'll cover both possibilities; Ground -> Green or Blue, +24V -> Red or Brown, and Input -> Black. Hook up the prox switch for the X to Input 2/PX and the Y prox switch to Input 3/PY.

Now you want to check to make sure the prox switch is working properly. They should be normally closed (NC), the led inside will be on and the input indicator on the ShopBot Position screen on the PC should be Green. If not check the settings in the SB software using the VN command. Set the switch mode for both #2 & #3 to Normally Closed Limit, also turn limits ON. Now put a piece of metal at the end of the switch to test that it is working correctly. If not check all of the wiring and try again. If the led on the switch doesn't come on when powered up or doesn't go off when putting a piece of metal at the end there is something mis-wired.

Once the prox switches are connected and fully functional you are read to home or use them as limts. The software is programmed to stop when a limit is hit and disregard them for the next move to allow them to be cleared off of the target and not make the operator answer a bunch of questions to get it clear of the target. If you go too far in the original direction you will be able to pass the target and most likely run into the hard stops. This all works using the keypad. Test this and you should be ready for homing and have limit switches.

01-24-2010, 07:26 PM
Thank you for the help. When I get back to school in the morning I can hook them up. I really appreciate the help. These forums are great resources.

Thanks again, Marc.