Upgrading to 24v
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For the fans you have a few options.
If you have other 12v fans you could supply the board with a seperate 12v rail that would go to just the fans via V_fan pin.
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If your endstops have LEDs in them, you'll need to change out the resistor for them, or remove the LEDs as they will be overpowered. Otherwise, you'll be fine going to 24V.Nevermind. The endstops use 3.3V.
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@makotosan thanks no just normal endstops no led at all
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@makotosan the endstops aren't exposed to 12v or 24v. 3.3v only.
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@phaedrux said in Upgrading to 24v:
For the fans you have a few options.
Is there any advantage for 4 wires fans? E.g. Duet detects if the fan stops working and shuts down?
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@phaedrux said in Upgrading to 24v:
If you have other 12v fans you could supply the board with a seperate 12v rail that would go to just the fans via V_fan pin.
This is the best way to go if you are interocking your V_IN supply on heater fault and also supplying 5VDC to the board to keep it alive. This way a stop doesn't risk a jammed hot end as the hotend fan stops.
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@zapta said in Upgrading to 24v:
@phaedrux said in Upgrading to 24v:
For the fans you have a few options.
Is there any advantage for 4 wires fans? E.g. Duet detects if the fan stops working and shuts down?
No I don't believe the Duet has the ability to read the RPM signal. The 4 wire fans can be made to work as PWM controlled, but without RPM.
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@phaedrux said in Upgrading to 24v:
@zapta said in Upgrading to 24v:
@phaedrux said in Upgrading to 24v:
For the fans you have a few options.
Is there any advantage for 4 wires fans? E.g. Duet detects if the fan stops working and shuts down?
No I don't believe the Duet has the ability to read the RPM signal. The 4 wire fans can be made to work as PWM controlled, but without RPM.
The current Duets can read and display the RPM of one 4-wire fan.
Duet WiFi hardware designer and firmware engineer
Please do not ask me for Duet support via PM or email, use the forum
http://www.escher3d.com, https://miscsolutions.wordpress.com -
@dc42 is there any capacity to react to a stopped fan?
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@phaedrux said in Upgrading to 24v:
@dc42 is there any capacity to react to a stopped fan?
Not currently.
I've remembered that RRF3 allows you to read the tacho sensor of more than one fan.
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@phaedrux said in Upgrading to 24v:
@dc42 is there any capacity to react to a stopped fan?
Definitely a valid thing to consider. It will come up on a risk assessment for anyone using a hotend mount (or fan duct) that can be melted by heat creaping back up the heat sink in the event of a fan failure.
I was thinking about a normally closed thermal switch on the cooler. That however needs a fair bit of mechanical work an won't be as quick as the firmware to react to fan failure.
@dc42 When you say RRF3 can read more than one fan do you mean on Duet 2 boards or only Duet 3? If the latter (and perhaps as a simple hack for a quick addition of this feature) the 'fan fault' could be triggered by not seeing a gcode specified minimum pulse rate when a specific (or multiple) heater read higher than say 80C? This way where hardware doesn't allow we could consider something like an arduino to monitor multiple signals and return an (all ok) pulse rate back to the duet.
Edit: things aren't quite as scarey as the predicted temperature for the heater at 100% at the mount end due to passive heat loss (perhaps poorly worded but not fan force cooled, e.g., radiated from the cooler and air convection) but where the E3D fan block contacts the cooler will still get very hot!
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@doctrucker said in Upgrading to 24v:
@dc42 When you say RRF3 can read more than one fan do you mean on Duet 2 boards or only Duet 3? If the latter (and perhaps as a simple hack for a quick addition of this feature) the 'fan fault' could be triggered by not seeing a gcode specified minimum pulse rate when a specific (or multiple) heater read higher than say 80C? This way where hardware doesn't allow we could consider something like an arduino to monitor multiple signals and return an (all ok) pulse rate back to the duet.
My question has already been answered. I need to look much more carefully at RRF3!
@dc42 said in wiki: Connecting and configuring fans:
Duet 3 will allow the RPM of multiple fans to be read. It’s possible that we may add this facility to Duet 2 as well, because Duet 2 and 3 will share most of the firmware source code.
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Yes it's possible to read multiple tachos on Duet 2 already, using RRF 3, if you have spare endstop inputs (not endstop inputs on a DueX). See https://duet3d.dozuki.com/Wiki/RepRapFirmware_3_overview.
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@phaedrux said in Upgrading to 24v:
@makotosan the endstops aren't exposed to 12v or 24v. 3.3v only.
That's right. Thanks for the correction.
