<p>Thanks to the comments, I was able to narrow down the specific issues in the firmware. The firmware version was really out of date, so I recommend finding the latest stable version.</p>

<p>Therefore, I found the latest stable version of Marlin, downloaded it, and created my own edited version. I went line by line in <code>configuration.h</code> and <code>configuration_adv.h</code>, with the old version I had side by side to the newer version, making any and all appropriate changes. Below are the lines I found most important to evaluate when setting up a second extruder.</p>

<p>Make sure the you have the right board selected from <code>boards.h</code>:</p>

<pre><code>#define MOTHERBOARD 34
</code></pre>

<p>Make sure the # of extruders is specified:</p>

<pre><code>#define EXTRUDERS 2
</code></pre>

<p>Make sure the sensor is active:</p>

<pre><code>#define TEMP_SENSOR_0 6
#define TEMP_SENSOR_1 6
#define TEMP_SENSOR_2 0
#define TEMP_SENSOR_BED 6
</code></pre>

<p>This should be considered:</p>

<pre><code>#define HEATER_0_MAXTEMP 240
#define HEATER_1_MAXTEMP 240
#define HEATER_2_MAXTEMP 240
#define BED_MAXTEMP 90
</code></pre>

<p>Everything under this comment should be looked at:</p>

<pre><code>// Preheat Constants
</code></pre>

<p>These would allocate the second extruder for other motors:</p>

<pre><code>#define Z_DUAL_STEPPER_DRIVERS
#define Y_DUAL_STEPPER_DRIVERS
#define DUAL_X_CARRIAGE
</code></pre>

<p>I'm sure there are other parameters I may have missed, and these are specific to my Prusa i3, but I hope this helps out anybody else in the future. </p>

CC BY-SA 3.0
2016-04-30T21:22:50.340Z
2016-04-30T21:22:50.340Z
Alex Sky
<p>I have a Folgertech Prusa i3, on a Ramps 1.4 with Marlin and I use Repetier-Host to control it. I am attempting to convert it to a dual extruder Bowden setup, and I can't seem to get the second extruder to work, although the first works just fine.</p>

<p>This is my problem:</p>

<p>I am not getting a reading in Repetier-Host for the thermistor of the second extruder. It is at a constant 100C.
When I turn on the cartridge heater for the second extruder in Repetier-Host, the cartridge heater does not heat up. </p>

<p>This is what I have done:</p>

<p>For the second extruder, I connected the wires from the thermistor to the pins for T2 and the wires for the cartridge heater to D9.
I have not updated anything in the Marlin firmware.
In Repetier-Host, I selected that there are two extruders, and a second extruder is indicated under the 'manual controls' tab.</p>

<p>This is what I have double checked:</p>

<p>I confirmed the second thermistor works because it indicates a proper temperature reading when plugging it in both T0 and T1.
I confirmed the second cartridge heater works because it heats up when connected to D10.</p>

<p>I apologize in advance if this is an amateur question, but I can't seem to find an answer anywhere. If somebody could at least point me in the right direction, or let me know if there is something I did not include in my post, I would really appreciate it, and hopefully it would help somebody else coming across a similar problem.</p>

<p>Thanks </p>

CC BY-SA 3.0
2016-04-25T02:55:15.617Z
i think you would need to recompile the firmware and set `#define EXTRUDERS 2` then `#define TEMP_SENSOR_1 <type>` etc etc. there are plenty of tutorials on the net
fukanchik
CC BY-SA 3.0
2016-04-30T15:21:55.880Z
It sounds like you need to modify various settings for the 2nd extruder. They are in Marlin, mainly in Configuration.h and pins.h. It's a bit of a pain since there are many #ifdef switches for different boards, printers, etc. Be sure you keep spare copies as you work. Try to work out just which #defines are getting applied in your situation, or just change all of (for example) the TEMP_SENSOR_1 #defines. It's tedious but doable.
TextGeek
CC BY-SA 3.0
2016-04-30T20:45:01.650Z
@TextGeek I appreciate the comment, and the direction to examine my firmware. That was indeed where my problem was. I now have it working.
Alex Sky
CC BY-SA 3.0
2016-04-30T20:45:39.780Z
@fukanchik I appreciate the comment, and the direction to examine my firmware. That was indeed where my problem was. I now have it working.
Alex Sky
<prusa-i3><ramps-1.4><software><marlin><dual-nozzle>
Prusa i3 Dual Extruder Setup Issues
Alex Sky
# Prusa i3 Dual Extruder Setup Issues

(Asked by: username_0 on 2016-04-24)

I have a Folgertech Prusa i3, on a Ramps 1.4 with Marlin and I use Repetier-Host to control it. I am attempting to convert it to a dual extruder Bowden setup, and I can't seem to get the second extruder to work, although the first works just fine.

This is my problem:

I am not getting a reading in Repetier-Host for the thermistor of the second extruder. It is at a constant 100C.
When I turn on the cartridge heater for the second extruder in Repetier-Host, the cartridge heater does not heat up.

This is what I have done:

For the second extruder, I connected the wires from the thermistor to the pins for T2 and the wires for the cartridge heater to D9.
I have not updated anything in the Marlin firmware.
In Repetier-Host, I selected that there are two extruders, and a second extruder is indicated under the 'manual controls' tab.

This is what I have double checked:

I confirmed the second thermistor works because it indicates a proper temperature reading when plugging it in both T0 and T1.
I confirmed the second cartridge heater works because it heats up when connected to D10.

I apologize in advance if this is an amateur question, but I can't seem to find an answer anywhere. If somebody could at least point me in the right direction, or let me know if there is something I did not include in my post, I would really appreciate it, and hopefully it would help somebody else coming across a similar problem.

Thanks

**Tags:** prusa-i3, ramps-1.4, software, marlin, dual-nozzle

> **Comments:**
> **username_1**: i think you would need to recompile the firmware and set `#define EXTRUDERS 2` then `#define TEMP_SENSOR_1 <type>` etc etc. there are plenty of tutorials on the net  
> **username_2**: It sounds like you need to modify various settings for the 2nd extruder. They are in Marlin, mainly in Configuration.h and pins.h. It's a bit of a pain since there are many #ifdef switches for different boards, printers, etc. Be sure you keep spare copies as you work. Try to work out just which #defines are getting applied in your situation, or just change all of (for example) the TEMP_SENSOR_1 #defines. It's tedious but doable.  
> **username_0**: @username_2 I appreciate the comment, and the direction to examine my firmware. That was indeed where my problem was. I now have it working.  
> **username_0**: @username_1 I appreciate the comment, and the direction to examine my firmware. That was indeed where my problem was. I now have it working.  

---

## 1 answers

### Answer by username_0 on 2016-04-30. Score: 4

Thanks to the comments, I was able to narrow down the specific issues in the firmware. The firmware version was really out of date, so I recommend finding the latest stable version.

Therefore, I found the latest stable version of Marlin, downloaded it, and created my own edited version. I went line by line in `configuration.h` and `configuration_adv.h`, with the old version I had side by side to the newer version, making any and all appropriate changes. Below are the lines I found most important to evaluate when setting up a second extruder.

Make sure the you have the right board selected from `boards.h`:

```
#define MOTHERBOARD 34

```

Make sure the # of extruders is specified:

```
#define EXTRUDERS 2

```

Make sure the sensor is active:

```
#define TEMP_SENSOR_0 6
#define TEMP_SENSOR_1 6
#define TEMP_SENSOR_2 0
#define TEMP_SENSOR_BED 6

```

This should be considered:

```
#define HEATER_0_MAXTEMP 240
#define HEATER_1_MAXTEMP 240
#define HEATER_2_MAXTEMP 240
#define BED_MAXTEMP 90

```

Everything under this comment should be looked at:

```
// Preheat Constants

```

These would allocate the second extruder for other motors:

```
#define Z_DUAL_STEPPER_DRIVERS
#define Y_DUAL_STEPPER_DRIVERS
#define DUAL_X_CARRIAGE

```

I'm sure there are other parameters I may have missed, and these are specific to my Prusa i3, but I hope this helps out anybody else in the future.


---

