Connecting Servo 1171MG TRAD-RACK
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Hi guys! I'm setting up my printer again
I'm converting it into a Voron 2.4 'giant' with the current print bed but in coreXY following the Voron project. I intended to add the TradRack to have the multi-color option. I need to purchase a 3hc board to connect additional motors for the Z axes. But I wanted to understand, in the TradRack configuration, you mount a servo motor 1171MG. Where do I connect it? How do I program it?Thanks a lot in advance!
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I am not familiar with TradRack, but to connect a conventional servo you use
M950
to define an IO as a servo, then useM280
as and when required to set the servo to a particular position. Alternatively, you can use an Out pin, but will need a pullup on it.I have a servo on IO7 on my MB6HC that opens and closes blades on a vent on the printer enclosure, so my config.sys has
; servo 1 on io7.out (note, needs to be 4, 5 or 7 as these are only PWM capable IO) M950 S1 C"io7.out" ; create servo 1 M280 P1 S10 ; set to 10 degree position, which is blades closed
and then when I want the vent open it is
M280 P1 S170
and when I want it closed it'sM280 P1 S10
Various things to note:
Not all IO headers can do PWM, but https://docs.duet3d.com/Duet3D_hardware/Duet_3_family/Duet_3_Expansion_3HC#inputoutput suggests that IO1 and IO4 on a 3HC can do it.
Servos are aggressive with the power supply. Consider putting it on its own supply. At least, put in a capacitor nearby. See https://docs.duet3d.com/en/User_manual/Connecting_hardware/Motors_servos#connecting-servo-motors. I have used the capacitor option, but mine is a lighter weaker servo than you are proposing, and my servo is moving a very low inertia mechanism.
Servos theoretically want 5V or more PWM signal. Some boards have a connector for a suitable control signal at 5V, but the particular servo I have used is happy at the standard 3.3V signalling on a IO pin with no treatment.
Use an 'ordinary' 'analogue' servo - what radio control calls 'analogue' servo uses the PWM signal that Duet boards generate (though they do it digitally). 'Digital' servos use a serial data stream on the wires and probably fall back to the old style control when they don't get that, but add an extra layer of possible confounding.
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1171MG is a DIGITAL servo, I don't have much experience with servo motors, I will have to do some tests.
I hope to find some info on TradRack, there's a genius who should have done it on RRF.Thank you very much!
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@nico-rast said in Connecting Servo 1171MG TRAD-RACK:
1171MG is a DIGITAL servo,
Well, that depends
JX Servo produce an analogue 1171MG (http://www.jx-servo.com/en/Product/MS/MAS/562.html) and a digital one (http://www.jx-servo.com/en/Product/MS/MDS/570.html). As noted, I suggest you use an analogue one.
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I plan on building a TradRack down the road with a "Fysetc stride max dual" as controllerboard, I however lost some of the steam when Annex announced they were moving away from open source tbh.
It's quite a few macros that need to be made to make it work like intended, in regard to servo control that's the easy part as long as you have a PWM capable output avalible for it.
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@Exerqtor Do you find it more difficult to communicate with a different board than the Duet? Or does it remain simple with the CAN bus and just a matter of assigning some addresses?
I didn't know that Annex was stepping out of the open-source project. If I see that it doesn't work well, I'll get the ERCF. Even though I've already built the trad-rack. My real issue is that there aren't many configurations for RRF, and I'm not very skilled in 'free' programming. I like to experiment, but I don't have any studies that could help me.