<p>I have one of these inductive sensors marked as <code>PL-08N</code> which should work within a <code>4-30 VDC</code> range and trigger at 8&nbsp;mm or less. It's clearly a knockoff, meaning it has no manufacturer marking and all info is printed on a sticker.</p>

<p><a href="https://i.sstatic.net/agBGz.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/agBGz.png" alt="enter image description here"></a></p>

<p>I'm testing it's functionality so I tried to wire <code>12 V</code> to <em>brown</em>, <code>GND</code> to <em>blue</em> and I'm probing the <em>black</em> wire, but I'm experiencing a weird behaviour: the sensor properly triggers, but it doesn't recover, meaning the LED won't turn off moving the sensor away from the plate and the black wire doesn't go back to <code>0 V</code>.</p>

<p>What am I missing?</p>

<p><strong>UPDATE</strong></p>

<p>Looking for solutions I tried to run the device at <code>5 V</code> (still within the declared range) expecting to have a very low sensitivity, just to discover:</p>

<ol>
<li>it activates at about 8 mm from the print bed (4 mm from my borosilicate glass)</li>
<li>it properly recovers immediately after I move it away</li>
</ol>

<p>I thought those devices had increased sensitivity with greater voltages...</p>

CC BY-SA 4.0
2019-02-27T14:54:54.423Z
You seem to have connected it correctly, indeed strange behavior. Once you remove a metal object the sensor should react on the change immediately. Could be a defective sensor.
0scar
CC BY-SA 4.0
2019-02-27T16:33:20.437Z
your later observation is interesting, but it might be how the device itself is set up: some devices are rated for a range and internally have some sort of regulator that results in actually just using a certain voltage, making them useable in a wider variety of systems.
Trish
CC BY-SA 4.0
2019-02-27T23:05:41.767Z
@Trish I fail to get how an internal regulator would cause the output to latch on activation when the supply gets higher well within the declared range... I mean, I'm not even getting close to the maximum allowed 30 V
Roberto Lo Giacco
<bed-leveling><inductive-sensor>
PL-08N inductive sensor not turning off
Roberto Lo Giacco
# PL-08N inductive sensor not turning off

(Asked by: username_0 on 2019-02-27)

I have one of these inductive sensors marked as `PL-08N` which should work within a `4-30 VDC` range and trigger at 8 mm or less. It's clearly a knockoff, meaning it has no manufacturer marking and all info is printed on a sticker.

[![enter image description here](https://i.sstatic.net/agBGz.png)](https://i.sstatic.net/agBGz.png)

I'm testing it's functionality so I tried to wire `12 V` to *brown*, `GND` to *blue* and I'm probing the *black* wire, but I'm experiencing a weird behaviour: the sensor properly triggers, but it doesn't recover, meaning the LED won't turn off moving the sensor away from the plate and the black wire doesn't go back to `0 V`.

What am I missing?

**UPDATE**

Looking for solutions I tried to run the device at `5 V` (still within the declared range) expecting to have a very low sensitivity, just to discover:

1. it activates at about 8 mm from the print bed (4 mm from my borosilicate glass)
2. it properly recovers immediately after I move it away

I thought those devices had increased sensitivity with greater voltages...

**Tags:** bed-leveling, inductive-sensor

> **Comments:**
> **username_1**: You seem to have connected it correctly, indeed strange behavior. Once you remove a metal object the sensor should react on the change immediately. Could be a defective sensor.  
> **username_2**: your later observation is interesting, but it might be how the device itself is set up: some devices are rated for a range and internally have some sort of regulator that results in actually just using a certain voltage, making them useable in a wider variety of systems.  
> **username_0**: @username_2 I fail to get how an internal regulator would cause the output to latch on activation when the supply gets higher well within the declared range... I mean, I'm not even getting close to the maximum allowed 30 V  

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## 0 answers

