Z tool pre-setter sensor wiring

RockB

@Phaedrux Understood, but the issue seems to be the Z probe not changing value in DWC even with manual triggering. The documentation says to expect 0 when not triggered and 1000 when triggered.

Checking the voltages using a multi-meter, I can clearly see the change from 1.9V to 19.8V with manually pressing the Z probe/switch.

Any suggestions on what is going on and why the Z probe value is not changing?

@dc42

oliof

@RockB it's possible the probe triggers and the print head lifts fast enough after triggering that DWC doesn't update the display

RockB

@oliof Thank you for the suggestion but there is no print head movement in this test. I am pressing the switch manually and actually holding it pressed for a few seconds. Still no change in Z probe reading shown in DWC and also in Object model.

Phaedrux

Firmware and DWC version?

RockB

@Phaedrux FW and DWC both at 3.5.2

droftarts

@RockB io3.in expects between 0V and 3.3V to trigger it, but has a threshold somewhere between (probably around 1.5 or 1.6V) between being not triggered and triggered. If you're getting between 1.9V and 24V, io3.in will be permanently triggered. The ! in the pin definition inverts this, so it is permanently NOT triggered. Did you add the 330 ohm resistor between io3.in and GND, as @dc42 suggested? This should pull down the 1.8V to 0V.

Does the LED light up on the switch?

Ian

RockB

@droftarts Ian, I tried adding the 330 ohm resistor between io3.in and GND - this causes the original 19.8V to drop to 3.2 V when switch is pressed (open); however in its closed (default) condition the voltage just drops from 1.9V to 1.8V. So now I am getting voltages in the range 1.8V to 3.2V and the lower voltage is still higher than the threshold for input pin.

LED does light up on the switch when powered (default state is NC) and goes off when pressed (open) as it should.

Any suggestions on how to further reduce the lower voltage so that it’s below the threshold? A circuit diagram would be helpful.

droftarts

@RockB I think you misunderstood @dc42's suggestion. It should be 24V > Switch > 2.2k resistor > io3.in > 330 ohm resistor > GND, ie a voltage divider circuit. Something like this:

The wire between the resistors connects to io3.in. Here's a circuit simulation: https://tinyurl.com/233sf6pk
With the switch closed, io3.in gets 3.3V. When it's open, it's not connected, so should be 0V.

Ian

RockB

@droftarts Ah! This makes sense. Will give this a try. Thanks

RockB

@droftarts Tested this and works as expected. Just changed the 2K resistor to a 2.7K resistor to limit the overall current below 10mA. Thanks