<p>I don't know that printer. But Arduino has a feature that a USB connection causes a reset. The Idea is that this helps when doing software update as the Arduino Boot loader will be active for one second after that reset.</p>

<p>This can be disabled, but needs hardware modification.</p>

CC BY-SA 3.0
2016-08-04T00:28:30.103Z
I'm on the same trail now but can't find the jumper which is common on Melzi boards. See http://3dprinting.stackexchange.com/questions/1590/where-is-the-auto-reset-jumper-on-the-wanhao-i3-plus?noredirect=1&lq=1
JRomero
CC BY-SA 3.0
2016-08-05T00:35:25.663Z
I answered your question there. Hope it helps.
Lars Pötter
CC BY-SA 3.0
2017-02-12T09:22:37.210Z
+1, I've been using Arduino for 3 years and never realised. From [Soft reset on arduino through starting serial comm](http://forum.arduino.cc/index.php?topic=26682.0): `The board resets the controller chip when there is a wiggle on the DTR line of the serial connection.  This lets the bootloader run again, which gives the Arduino IDE a chance to upload a new sketch that replaces the old sketch.  If no such upload happens, the old sketch is started again from the beginning.`
Greenonline
CC BY-SA 3.0
2016-08-04T00:21:09.980Z
2016-08-04T00:21:09.980Z
Lars Pötter
<p>That is normal on most printers. They restart if you connect.</p>

<p>As you have an SD card slot I would recommend using it rather than your computer. If your connected computer goes to sleep it would also reset the connection after wakeup.</p>

CC BY-SA 3.0
2016-08-04T00:50:39.323Z
Although I agree with you about preference on using SD card I'm actually running a lot of 10 minute calibration tests to determine best print settings having to do this time and time again for via SD Card is painful.
JRomero
CC BY-SA 3.0
2016-08-04T00:48:30.357Z
2016-08-04T00:48:30.357Z
ftobler
<p>I just received my Wanhao Duplicator i3 PLUS. Everything prints and functions fine via SD card and the display but when connecting to my Mac computer the printer seems to restart.</p>

<ul>
<li>Baud Rate: 115200</li>
<li>Serial Port: <code>/dev/tty.wchusbserial1420</code></li>
</ul>

<p>Any ideas what it could be?</p>

<arduino-mega-2650><wanhao>
Wanhao i3 PLUS restarts when connecting USB
JRomero
# Wanhao i3 PLUS restarts when connecting USB

(Asked by: username_0 on 2016-08-03)

I just received my Wanhao Duplicator i3 PLUS. Everything prints and functions fine via SD card and the display but when connecting to my Mac computer the printer seems to restart.

* Baud Rate: 115200
* Serial Port: `/dev/tty.wchusbserial1420`

Any ideas what it could be?

**Tags:** arduino-mega-2650, wanhao

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## 2 answers

### Answer by username_1 on 2016-08-04. Score: 3 | Accepted answer

I don't know that printer. But Arduino has a feature that a USB connection causes a reset. The Idea is that this helps when doing software update as the Arduino Boot loader will be active for one second after that reset.

This can be disabled, but needs hardware modification.

> **Comments:**
> **username_0**: I'm on the same trail now but can't find the jumper which is common on Melzi boards. See http://3dprinting.stackexchange.com/questions/1590/where-is-the-auto-reset-jumper-on-the-wanhao-i3-plus?noredirect=1&lq=1  
> **username_1**: I answered your question there. Hope it helps.  
> **username_2**: +1, I've been using Arduino for 3 years and never realised. From [Soft reset on arduino through starting serial comm](http://forum.arduino.cc/index.php?topic=26682.0): `The board resets the controller chip when there is a wiggle on the DTR line of the serial connection.  This lets the bootloader run again, which gives the Arduino IDE a chance to upload a new sketch that replaces the old sketch.  If no such upload happens, the old sketch is started again from the beginning.`  

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### Answer by username_3 on 2016-08-04. Score: 1

That is normal on most printers. They restart if you connect.

As you have an SD card slot I would recommend using it rather than your computer. If your connected computer goes to sleep it would also reset the connection after wakeup.

> **Comments:**
> **username_0**: Although I agree with you about preference on using SD card I'm actually running a lot of 10 minute calibration tests to determine best print settings having to do this time and time again for via SD Card is painful.  

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