MK5 + relay board = so noisy
Marty McGuire
I just got my MK5 working with the relay board, and it is noisy as all
hell. The relay buzzes and sings whenever the extruder controller
tries to PWM the board at a value that isn't 0 or 255.
Is there a fix to make the firmware stop PWMing the relay board?
Ideally there is a quick setting like a PID parameter (best because it
is easy), or a firmware Configuration.h flag.
Thanks,
Marty
Jordan Miller
jordan
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Marty McGuire
does control the heater through PWM:
PWM (pulse-width modulation) is a kind of frequency modulation. At a
PWM of 0, the relay is off. At a PWM of 255, the relay is on. For
values close to 255, the relay just counts them as "close enough" to
on. As the PWM drops to zero, the relay attempts to keep up with the
changes in the signal, resulting in a "whining", "singing", or
"buzzing", depending on how low the PWM value is.
The heated build platform is not controlled by PWM, so it should be
possible to drive the extruder heater similarly.
Thanks,
Marty
M.Rule
with PWM. This is not the sort of operation relays are spec'd for. I'm
not an electrical engineer, but it seems to me that the only two
reasonable things to do might be to disable PWM in the firmware or use
a solid state relay.
are H bridges the same thing as solid state relays ?
tmo
On Aug 27, 10:19 pm, "M.Rule" <mrule7...@gmail.com> wrote:
> I really can't believe that MakerBot intended to run the relay boards
> with PWM. This is not the sort of operation relays are spec'd for. I'm
> not an electrical engineer, but it seems to me that the only two
> reasonable things to do might be to disable PWM in the firmware or use
> a solid state relay.
>
> are H bridges the same thing as solid state relays ?
>
> > In another thread, beak90 pointed out that the extruder controller
> > does control the heater through PWM:
>
> > PWM (pulse-width modulation) is a kind of frequency modulation. At a
> > PWM of 0, the relay is off. At a PWM of 255, the relay is on. For
> > values close to 255, the relay just counts them as "close enough" to
> > on. As the PWM drops to zero, the relay attempts to keep up with the
> > changes in the signal, resulting in a "whining", "singing", or
> > "buzzing", depending on how low the PWM value is.
>
> > The heated build platform is not controlled by PWM, so it should be
> > possible to drive the extruder heater similarly.
>
> > Thanks,
> > Marty
>
> >> wait, i thought the extruder controller doesn't PWM the board, it just does on/off. PWM is only for the motor H-bridges. When you use relay board to drive the heater, it is on or off, and it cycles the frequency (clickety-clack rate), not the amplitude. right?
>
> >> jordan
>
> >> On Aug 27, 2010, at 7:59 PM, Marty McGuire wrote:
>
> >>> Hi again all,
>
> >>> I just got my MK5 working with the relay board, and it is noisy as all
> >>> hell. The relay buzzes and sings whenever the extruder controller
> >>> tries to PWM the board at a value that isn't 0 or 255.
>
> >>> Is there a fix to make the firmware stop PWMing the relay board?
> >>> Ideally there is a quick setting like a PID parameter (best because it
> >>> is easy), or a firmware Configuration.h flag.
>
> >>> Thanks,
> >>> Marty
>
> >>> --
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Marty McGuire
So I'm wondering how other folks who have the MK5 working are running it?
Thanks,
Marty
Jordan Miller
is your mk5 well heat-insulated? that should decrease the temp fluctuations and the wear on the relay board.
jordan
Rob Giseburt
-Rob
Marty McGuire
and the "thermal cape".
Picture: http://static.camura.com/media/images/o/ea0b295633abd7a1ec7da87b06da4753.jpg
The temp swings by more than +/-10 degrees over the course of a couple
of minutes.
Here's a pic of the temp curve in RepG:
http://static.creatingwithcode.com.s3.amazonaws.com/mk5_temp_swings-2010-08-28.png
Is anybody successfully running an MK5 from a relay board? If so, can
you share your experiences? :)
Thanks,
Marty
Nathan Hilderman
backwards. Not related to solid state relay. I think a pair of good
FETs (IRF540) with heat sinks is the way to go.
Nate True
say once a minute. The PWM my extruder uses either has the relay on
or off (and makes an annoying high-pitched noise pretty often). I
expect this to wear out the relay pretty quickly so I want to switch
to an external MOSFET board here pretty quick, which I plan to build.
My biggest fear with the relay board is the relay will fail in the
closed position, causing the heaters to run out of control and turn my
Makerbot into a sentient killing robot like on Transformers, which I
would prefer not to happen.
I expect a future extruder controller update will add an option to
shut off the PWM for those of us without sentient killing Makerbots.
One thing that always bothered me about that movie was that machines
brought to life with the All-Spark(tm) were by default evil angry
killing robots with guns, not compassionate robots like the auto-bots.
What's with that?
On Aug 28, 7:42 am, Marty McGuire <schmartiss...@gmail.com> wrote:
> The room air is still and I insulated the MK5 with the ceramic tape
> and the "thermal cape".
>
> The temp swings by more than +/-10 degrees over the course of a couple
> of minutes.
>
> Here's a pic of the temp curve in RepG:
>
> Is anybody successfully running an MK5 from a relay board? If so, can
> you share your experiences? :)
>
> Thanks,
> Marty
>
>
>
>
>
>
>
> On Sat, Aug 28, 2010 at 10:23 AM, Jordan Miller <jrdn...@gmail.com> wrote:
> > can you post a pic of your temp curves from repG? Is it really fluctuating a lot? I have run an extruder and HBP from the relay board and it's nowhere near as loud as I thought it might be.
>
> > is your mk5 well heat-insulated? that should decrease the temp fluctuations and the wear on the relay board.
>
> > jordan
>
>
> >> Yeah, it's not sustainable to run the relay board like that.
>
> >> So I'm wondering how other folks who have the MK5 working are running it?
>
> >> Thanks,
> >> Marty
>
M.Rule
boards if the system is actually trying to PWM the relays. This is
kind of a really .. really .. obvious design failure. Apart for
killing the relays, its also going to introduce tonnes of
interference, I wouldn't be surprised if this worsens the interference
problems. Again, not trying to be unkind to MakerBot, but I think
there is absolutely no excuse for this design flaw. Don't they have
any electrical engineers on the premises to say "wait a minute, thats
an really obviously awful design, either make this software fix such
that it doesn't PWM, or use solid state components"? I'm pretty sure
the community was asking about this exact problem before the relay
board was released, and MakerBot said something like "no, its fine, we
swear". Well, however people are hooking in the relay boards now is
clearly not fine if PWM signals are being sent to mechanical relays.
beak90
controlled without PWM. Its somewhere in configuration.h. You'll have
to recompile the firmware though.
On Aug 28, 9:14 am, "M.Rule" <mrule7...@gmail.com> wrote:
> MakerBot needs to release a firmware patch for anyone using the relay
> boards if the system is actually trying to PWM the relays. This is
> kind of a really .. really .. obvious design failure. Apart for
> killing the relays, its also going to introduce tonnes of
> interference, I wouldn't be surprised if this worsens the interference
> problems. Again, not trying to be unkind to MakerBot, but I think
> there is absolutely no excuse for this design flaw. Don't they have
> any electrical engineers on the premises to say "wait a minute, thats
> an really obviously awful design, either make this software fix such
> that it doesn't PWM, or use solid state components"? I'm pretty sure
> the community was asking about this exact problem before the relay
> board was released, and MakerBot said something like "no, its fine, we
> swear". Well, however people are hooking in the relay boards now is
> clearly not fine if PWM signals are being sent to mechanical relays.
>
Mark Cohen
board lasts a year, I think I've got my money's worth. I think I would use
the new one when I get it for a few hundred hours also before I would be
able to say if there is a problem or not and I do not recall them saying it
was quiet.
Mark Cohen
time. Aside from your thoughts on the relay failing closed, there are so
many other things that can go wrong.
-----Original Message-----
From: make...@googlegroups.com [mailto:make...@googlegroups.com] On Behalf
Brendan
not experience the noise. It clicks when it goes on and off but not a
constant clicking. I do have significant (about +5/-13) temp swings
and am futzing with PID settings to little avail. I've got the HBP
also. It took some time to get them working together but they do now.
MB firmware: 2.1
Extruder firmware: 2.3
Don't think it matters but:
B- (ground) and B+ (hot) outputs from Extruder controller to A- and A+
inputs on relay. A outputs on relay to MK5.
A- (ground) and A+ (hot) outputs from Extruder controller to B inputs
on relay and they output to the HBP.
I mention these because I tried different combinations of inputs/
outputs before it worked. Suspect it was just poor physical
connections since it shouldn't matter but, above is what finally
worked.
Joheinz
HBP and the relay board, and though I am currently doing some other
maintenance work, I did not experience any of the problems mentioned
in this thread so far.
When I turn the HBP on, it heats up pretty fast (to e.g. 110 degrees),
swings a bit around +/- 3 degrees and then stabilizes and really keeps
a constant temperature of 110 degrees with the occassional flicking of
the relay. If it stays like this I would not be very worried about the
use of a relay instead of MOSFETS and if I really do not have anything
else to do, I would exchance the 1N4001 quenching diodes as they are
pretty slow and quenching diodes need to be fast. But I guess this
would be electronic cosmetics.
Markus
2010/8/29 Brendan <bre...@whatsnewla.com>:
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M.Rule
Marty McGuire
with the latest version of the G3Firmware on Github, so it must be
compiled from source.
Basically, when driving a heater through the relay board, the software
should be using plain on/off controls. The code to run the HBP was
written with this in mind, but the extruder software expected to be
able to use "analog" values of heating, rather than on/off.
Adam added a quick fix to the extruder heating code to allow it to
work with on/off control, if you compile from source with a
"relays=true" flag.
You can check out the firmware source using Git:
$ git clone git://github.com/makerbot/G3Firmware.git
There is discussion about how to compile and upload the firmware, and
on how to tweak your PID (temperature matching) parameters in the rest
of the thread:
http://groups.google.com/group/makerbot/browse_thread/thread/cbc2887983fca9b/c7fc71116fbb38df?q=mk5+pid&lnk=nl&
Thanks,
Marty
vex
dorm room quiet... Anyone have success with hacking together external
power MOSFETS or SSRs? Or some kind of insulation (high frequency =
small/easy)?.
Rob Giseburt
click here and there, like a pen, versus a nasty buzzing and clacking
with the wrong firmware.
-Rob