Research On Inductive Proximity Sensors - Revision history

Tobben: /* LJ12A3-4-Z/BX */

2016-02-16T11:15:54Z

LJ12A3-4-Z/BX

← Older revision		Revision as of 11:15, 16 February 2016
Line 59:		Line 59:
	BLUE ----------------GND		BLUE ----------------GND

	Other solutions are presented in [http://forums.reprap.org/read.php?219,477467,477467 this forum thread], [https://www.youtube.com/watch?v=EcGFLwj0pnA Thomas Sanladerer's video], in the video comments and [http://www.me.ua.edu/me360/spring05/Notes/Topic21-Proximity_Switches_sv.pdf University of Alabama course material].		Other solutions are presented in [http://forums.reprap.org/read.php?219,477467,477467 this forum thread], [https://www.youtube.com/watch?v=EcGFLwj0pnA Thomas Sanladerer's video], in the video comments and [http://www.me.ua.edu/me360/spring05/Notes/Topic21-Proximity_Switches_sv.pdf University of Alabama course material] (bottom of document).

Tobben at 11:15, 16 February 2016

2016-02-16T11:15:13Z

← Older revision		Revision as of 11:15, 16 February 2016
Line 59:		Line 59:
	BLUE ----------------GND		BLUE ----------------GND

	Other solutions are presented in [http://forums.reprap.org/read.php?219,477467,477467 this forum thread], [https://www.youtube.com/watch?v=EcGFLwj0pnA Thomas Sanladerer's video] ~~and~~ in the video comments.		Other solutions are presented in [http://forums.reprap.org/read.php?219,477467,477467 this forum thread], [https://www.youtube.com/watch?v=EcGFLwj0pnA Thomas Sanladerer's video], in the video comments and [http://www.me.ua.edu/me360/spring05/Notes/Topic21-Proximity_Switches_sv.pdf University of Alabama course material].

Tobben at 11:10, 16 February 2016

2016-02-16T11:10:22Z

← Older revision		Revision as of 11:10, 16 February 2016
Line 59:		Line 59:
	BLUE ----------------GND		BLUE ----------------GND

	Other solutions are presented in [http://forums.reprap.org/read.php?219,477467,477467 this forum thread], .		Other solutions are presented in [http://forums.reprap.org/read.php?219,477467,477467 this forum thread], [https://www.youtube.com/watch?v=EcGFLwj0pnA Thomas Sanladerer's video] and in the video comments.

Tobben: /* Wiring */

2016-02-16T11:09:49Z

Wiring

← Older revision		Revision as of 11:09, 16 February 2016
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	BLACK -----\|<--- uP		BLACK -----\|<--- uP
	BLUE ----------------GND		BLUE ----------------GND

			Other solutions are presented in [http://forums.reprap.org/read.php?219,477467,477467 this forum thread], .

Tobben: /* LJ12A3-4-Z/BX */

2016-02-16T11:01:58Z

LJ12A3-4-Z/BX

← Older revision		Revision as of 11:01, 16 February 2016
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	3 wire, NPN, NO		3 wire, NPN, NO

	Needs to be supplied 6-36 V. This means we need to build a voltage divider to interface with RAMPS logic.		Needs to be supplied 6-36 V. This means we might need to build a voltage divider to interface with RAMPS logic.
	Some reports having gotten 6 V sensors to work by feeding them the Arduino's 5 V [http://forums.reprap.org/read.php?219,477467,477467], so we should try that first.		Some reports having gotten 6 V sensors to work by feeding them the Arduino's 5 V [http://forums.reprap.org/read.php?219,477467,477467], so we should try that first.

Tobben: /* LJ12A3-4-Z/BX */

2016-02-16T11:01:31Z

LJ12A3-4-Z/BX

← Older revision		Revision as of 11:01, 16 February 2016
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	Needs to be supplied 6-36 V. This means we need to build a voltage divider to interface with RAMPS logic.		Needs to be supplied 6-36 V. This means we need to build a voltage divider to interface with RAMPS logic.
	Some reports having gotten 6 V sensors to work by feeding them the Arduino's 5 V [http://forums.reprap.org/read.php?219,477467,477467], so we should try that first.		Some reports having gotten 6 V sensors to work by feeding them the Arduino's 5 V [http://forums.reprap.org/read.php?219,477467,477467], so we should try that first.

			The most robust solution has been published by Kostas Karouzos in a Youtube comment.
			It's not possible to link to youtube comments directly, but [https://www.youtube.com/watch?v=EcGFLwj0pnA&lc=z12kcpnrtuqvhznrh04cft1xbmzgz3yyoew this link] will at least place the comment at the top of the comments section of the video.

			Hi. I am using an LJ12A3-4-Z/BX.(NPN, NO). I powered it from 12 Volts. Tried both the resistor voltage divider and the regulator and they both work.
			However, the high value isn't exactly 5 Volts, and the LED on the sensor is always on, a little darker when the sensor is not triggered. (That has no functionality effect, I just don't like it)
			The reason why that happens is because the sensor's output is actually open collector, and the only thing sourcing 12 Volts to the output when the sensor is not triggered is the led circuit, which also has a 10k resistor.
			A better solution to interface the sensor to the board is to use just a diode, like this:
			- brown wire to 12 Volts,
			- blue wire to Gnd
			- black wire to the cathode of the diode
			- anode of the diode to the processor input
			- internal pull-up enabled!
			Any diode would work, I used a 1N4148.
			Now the processor 'sees' 5Volts for high and ~0.6Volts for Low (diode forward drop), which is perfectly safe.
			And the LED turns on only when the sensor is triggered!
			Schematic:
			BROWN ---------- 12V
			BLACK -----\|<--- uP
			BLUE ----------------GND

Tobben at 10:19, 16 February 2016

2016-02-16T10:19:55Z

← Older revision		Revision as of 10:19, 16 February 2016
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	*Less sensitive to bed irregularities than capacitive sensing.		*Less sensitive to bed irregularities than capacitive sensing.

			= General how to guides =
			[https://www.youtube.com/watch?v=EcGFLwj0pnA Thomas Sanladerer's video]

	= Models =		= Models =

Tobben at 09:41, 16 February 2016

2016-02-16T09:41:58Z

← Older revision		Revision as of 09:41, 16 February 2016
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	NC, NO, PNP and NPN defines the wiring interface but is not relevant to the sensing itself.[https://sensortech.wordpress.com/2011/01/18/industrial-sensing-fundamentals-%E2%80%93-back-to-the-basics-npn-vs-pnp/]		NC, NO, PNP and NPN defines the wiring interface but is not relevant to the sensing itself.[https://sensortech.wordpress.com/2011/01/18/industrial-sensing-fundamentals-%E2%80%93-back-to-the-basics-npn-vs-pnp/]

	= [[3D_Printer_Bed_Leveling#Assessment_Matrix Assessment Matrix]] Results on Inductive Sensing =		= [[3D_Printer_Bed_Leveling#Assessment_Matrix\|Assessment Matrix]] Results on Inductive Sensing =
	Sensor weighs ~45 grams and is most often placed near print head.		Sensor weighs ~45 grams and is most often placed near print head.
	The added moving weight is regarded as the major drawback of that bed probe solution, as compared to the others.		The added moving weight is regarded as the major drawback of that bed probe solution, as compared to the others.

Tobben at 09:41, 16 February 2016

2016-02-16T09:41:38Z

← Older revision		Revision as of 09:41, 16 February 2016
Line 7:		Line 7:
	NC, NO, PNP and NPN defines the wiring interface but is not relevant to the sensing itself.[https://sensortech.wordpress.com/2011/01/18/industrial-sensing-fundamentals-%E2%80%93-back-to-the-basics-npn-vs-pnp/]		NC, NO, PNP and NPN defines the wiring interface but is not relevant to the sensing itself.[https://sensortech.wordpress.com/2011/01/18/industrial-sensing-fundamentals-%E2%80%93-back-to-the-basics-npn-vs-pnp/]

	= ~~Summary of~~ [[3D_Printer_Bed_Leveling#Assessment_Matrix]] Results on Inductive Sensing =		= [[3D_Printer_Bed_Leveling#Assessment_Matrix Assessment Matrix]] Results on Inductive Sensing =
	Sensor weighs ~45 grams and is most often placed near print head.		Sensor weighs ~45 grams and is most often placed near print head.
	The added moving weight is regarded as the major drawback of that bed probe solution, as compared to the others.		The added moving weight is regarded as the major drawback of that bed probe solution, as compared to the others.

Tobben at 09:40, 16 February 2016

2016-02-16T09:40:20Z

@@ Line 1: / Line 1: @@
-The short [http://machinedesign.com/sensors/proximity-sensors-compared-inductive-capacitive-photoelectric-and-ultrasonic machinedesign.com article] is a good introduction.
+Inductive proximity sensors are circuits that maintain a oscillating magnetic fields while sensing the reluctance of the circuit through the voltage amplitude of the oscillation.
 The magnetic fields induce eddy currents in proximate ferrous materials.
-These eddy currents create their own magnetic fields, opposing the one created by the sensor and increasing sensor circuit (coil) reluctance.
+Since eddy currents create opposing magnetic fields, reluctance in the sensor circuit (which contains a coil) increases.[http://machinedesign.com/sensors/proximity-sensors-compared-inductive-capacitive-photoelectric-and-ultrasonic]
 == LJ12A3-4-Z/BX ==
-This is the sensor model supplied by Folgertech [http://folgertech.com/products/lj12a3-4-z-bx-inductive-proximity-sensor-switch here].