<p>I’m in the process of installing a BLTouch on a Velleman Vertex K8400. The board doesn’t have a dedicated servo pin, so I’ll assign one. No problem there.</p>
<p>The board only has a Z-min pin, so it’s my understanding that I’m supposed to unplug my Z-min cable and plug the BLTouch into the Z-min port.</p>
<p>My question is: &quot;Can't I assign another unused pin as a Z-max, plug the BLTouch into that, adjust the firmware, and leave the existing Z-min sensor plugged in?&quot;</p>
<p>Upon further review, I probably shouldn't have said Z-max, and will be more specific.</p>
<p>This is a Mega 2560 board with 2 available PWM pins. Anything wrong with this setup?</p>
<p>Pins.h:</p>
<pre>
  #define SERVO_0_PIN 15 //PH3 (PWM)
  
  #define Z_MIN_PROBE_PIN 16 //PH4 (PWM)
</pre>
<p>Configuration.h:</p>
<pre>
=======Z Probe Option=======

  #define Z_MIN_PROBE_ENDSTOP

  #define BLTOUCH
</pre>
<p>I want be able to keep my Z-min sensor plugged in as a backup to prevent a bed crash just in case the BL touch doesn't trigger. From what I see this should work as long as I make sure the BLTouch triggers before the Z-min. Any issues that anyone can see?</p>

[{'answer_id': 9868, 'author': '0scar', 'author_id': 5740, 'author_profile': 'https://3dprinting.stackexchange.com/users/5740', 'pm_score': 2, 'selected': False, 'text': '<p><strong><em>Note</strong>: The question has changed after posting this answer. This answer answered the previous question, but is now out-of-date with respect to how the question has changed; I\'ll update it later, as it is possible what is asked now.</em></p>\n\n<hr>\n\n<p>You can change the Z-min and the Z-max pin assignment in Marlin Firmware in the <code>pins_&lt;boardname&gt;.h</code> file, you basically exchange the Z-min and the Z-max. Note that the switch connected to the old Z-min port now becomes a Z-max sensor if you enable that in the firmware; you should therefore remove it (the actual switch) from the minimum Z position.</p>\n\n<hr>\n\n<p>To enable a BLTouch sensor you require 2 pins free on the microprocessor. One registers the signal of the trigger, the other triggers the servo to stow/deploy the sensor.</p>\n\n<p>You can connect the white/black to the Z-min signal (Z-min pin) and ground of the Z-min connector (or if pins are swapped in the firmware to the Z-max). The other wires need to be connected to +5&nbsp;V (red), ground (brown) and orange/yellow to a free analog pin (PWM pin):</p>\n\n<blockquote>\n  <p><a href="https://www.indiegogo.com/projects/bltouch-auto-bed-leveling-sensor-for-3d-printers#/" rel="nofollow noreferrer">BLTouch can be operated in the following condition.</a><br>\n  - One I/O for control (PWM or Software PWM)<br>\n  - One I/O for Zmin (Z Probe)<br>\n  - GND and +5&nbsp;V power</p>\n</blockquote>\n\n<p>The PWM pin should be defined in your <code>pins_&lt;boardname&gt;.h</code> file, e.g.:</p>\n\n<pre><code>#define SERVO0_PIN         5 // RUMBA board\n</code></pre>\n\n<p>or</p>\n\n<pre><code>#define SERVO0_PIN         27 // ANET board\n</code></pre>\n\n<p>The Z-max signal pin is no PWM pin for the servo.</p>\n'}, {'answer_id': 9925, 'author': 'Glen Hoffman', 'author_id': 16358, 'author_profile': 'https://3dprinting.stackexchange.com/users/16358', 'pm_score': 2, 'selected': False, 'text': '<p>After studying the Marlin code, I found the answer I was looking for.</p>\n<p>If I have a spare PWM pin, I can assign it to anything I want. So the best solution is to define the pin as a <code>Z_MIN_PROBE</code> and then in <code>Configuration.h</code> in the Bltouch settings</p>\n<pre><code>#define Z_MIN_PROBE_ENDSTOP\n</code></pre>\n<p>rather than</p>\n<pre><code>#define Z_MIN_ENDSTOP_USES\n</code></pre>\n'}]
['https://3dprinting.stackexchange.com/questions/9867', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/16358/']