Skip to main content

Site Navigation

Your Account

Choose Language

Help

Revision to Connecting and configuring fans

David Crocker

== Overview ==
 
* The Duet 2 (WiFi an Ethernet) hasWiFi and Ethernet boards have three controlled fan connectors FAN0, FAN1 and FAN2 plus two always-on fan connectors. A jumper (V_FAN) allows you to select whether all fans are powered from the VIN supply or from the Duet's 5V supply. FAN1 is on by default at power up, for maximum safety when you configure it as a thermostatically-controlled fan.
* The Duet 2 Maestro has three controlled fan connectors FAN0, FAN1 and FAN2 plus one always-on fan connector. The fan voltage is jumper-selectable in 2 blocks.
* The Duet 2 (WiFi an Ethernet) hasWiFi and Ethernet boards have three controlled fan connectors FAN0, FAN1 and FAN2 plus two always-on fan connectors. A jumper (V_FAN) allows you to select whether all fans are powered from the VIN supply or from the Duet's 5V supply. FAN1 is on by default at power up, for maximum safety when you configure it as a thermostatically-controlled fan.
* The Duet 2 Maestro has three controlled fan connectors FAN0, FAN1 and FAN2 plus one always-on fan connector. The fan voltage is jumper-selectable in 2 blocks.
* Our intention is that in a 3D printer with a single print head, you use the''' Fan0 output for the print cooling fan''' and the '''Fan1 output for the heatsink fan'''. This is the easiest configuration to use because it's what the firmware expects by default.
* The Duex 2 and Duex 5 have 6 further PWM controllable fans (FAN3 - FAN8). ''(Versions before 0.8 had 5 fan connections see the [[Duex2 and Duex5 Features|Duex hardware page]]for details)''
* The Duet 0.8.5 has two controlled fan connectors FAN0 and FAN1 plus two always-on fan connectors.
 
Mixed-voltage setups are not directly supportedsupported on the Duet 2 WiFi/Ethernet, but the Duet switches the fans' connections to ground, so you may be able to connect each fan's positive side to the appropriate voltage and its negative side to the appropriate pin on the Duet. Each controlled fan can be configured in firmware as a gcode controlled fan or as a thermostatically-controlled fan.
Mixed-voltage setups are not directly supportedsupported on the Duet 2 WiFi/Ethernet, but the Duet switches the fans' connections to ground, so you may be able to connect each fan's positive side to the appropriate voltage and its negative side to the appropriate pin on the Duet. Each controlled fan can be configured in firmware as a gcode controlled fan or as a thermostatically-controlled fan.
 
We recommend no more than 1.5A continuous current draw from each fan output, although 3up to 4A3.5A for a few seconds while the fan starts up will not harm them.
We recommend no more than 1.5A continuous current draw from each fan output, although 3up to 4A3.5A for a few seconds while the fan starts up will not harm them.
 
For details of the configuration options available for various firmware versions see the [[Gcode#Section_M106_Fan_On|M106 gcode section]]
** Divide this value into the V_FAN voltage (typically you will use V_IN) to get the peak current at startup.
** If this peak current is greater than 3A then you should connect a surge reducing thermistor in series with the fan to reduce the startup current. Here is an example of a thermistor that may be suitable: http://uk.farnell.com/epcos/b57236s0250m000/thermistor-ntc/dp/9751904.
** Alternatively, if you have a spare heater output and you are using firmware 2.02 or later then you can use the heater output as an additional fan output (see later). You must always use a flyback diode if you connect a brushed DC motor to a heater output.
 
== Always-on fans ==
== Using a fan connector as a general purpose output ==
 
If you use the I-1 parameter in the m106M106 command for a fan, then the fan is disabled which frees up the pin for use as a general purpose I/O pin that can be controlled using M42.
If you use the I-1 parameter in the m106M106 command for a fan, then the fan is disabled which frees up the pin for use as a general purpose I/O pin that can be controlled using M42.

To undo the changes made by this version, click 'Revert Changes.' This will automatically restore the previous version of this guide.

Revert Changes