NPN home proximity switch

[Upnorth4]

I am having trouble with the voltage dropping on my proximity switches.
I purchased some 5vlt prox switches, when they aren’t connected to my C-10 bob the switch behaves well, provides 5vlts until there is metal within range. I have the blue wire to negative, brown wire to 5vkt off the board, black wire to my multi meter. However when unconnected it to pin 13 the voltage drops to 1.3vlts.
This is not enough voltage to provide a signal.
I have pin13 set to Yaxis active low.

Why is the voltage dropping so much when it is connected?

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[john-100]

on the C10 breakout board you need to set the input jumper to pull up the input terminals to +5V
as the NPN output of the proximity switch can only connect the black output wire to the blue negative supply wire
when the transistor is switched on

the jumper on the C10 board has to connect the 4K7 resistor between the input & +5V
so the C10 input can see the logic level change when the proximity switch is off



as the proximity switch is normally open

you will need to set the input to active low in mach3 to match the switch you have (or what ever software your using)

I can only assume there must be a high impedance path between the switches positive supply terminal and the output terminal
probably a LED status indicator built into the proximity switch

the meter you used will have a high input impedance so you will see the output change as expected but when loaded down to 0V by a 4K7 resistor when the C10 input pull down is selected


John

[Upnorth4]

I can only assume there must be a high impedance path between the switches positive supply terminal and the output terminal
probably a LED status indicator built into the proximity switch

the meter you used will have a high input impedance so you will see the output change as expected but when loaded down to 0V by a 4K7 resistor when the C10 input pull down is selected


John

Thank you for he reply.
Will I have to add any components? It appears that all components to the left of the dashed line are on the BOB.

Currently my jumper is set to pull down.

How is a touch probe set up with it set to pull up?

[Upnorth4]

John,
Thank you!
I switched the jumper to "pull-up" and the 5vlt NPN proximity sensors work perfectly. No added resistors.
I did find a diagram on the probe set up in the C-10 manual. With the input set to pull-up 5vlts is sent out to the probe lead, I added a ground to the table and switched the probe to "active low" on Mach3.

Very happy about this as the sensors are very small.

Next issue though is noise. I have only hooked up on sensor to the Y axis home and I am getting "crunchy" intermittent small movement on my X and Y axis steppers.

Is it possible to add shielding to cheap sensor wires?

[john-100]

only just been able to reply
for a couple of days , only been able to connect to cloudflare London
initially had error 504 Gateway time-out
then Server Error 503 Service Temporarily Unavailable
for the connection to CNCzone server


as you have found

you don't need to add any components

every thing to the left of the dashed line is one of the C10's five input circuits

in the diagram the jumper for pins 10 – 13 and 15 is shown set to pull up


do the sensors have a metal case?

details of how you have wired the machine will help to work out if you have any earth loops
that are introducing noise into the control system

John