Posts made by Vaei

The bed I bought didn't have a thermistor, so I bought a separate one and I think the issue could also be the values being entered incorrectly. I'll have to measure the coefficients. But.. right now I have no time whatsoever (and sorry for the delayed response), I'll have to get back in a week or so.

@phaedrux I don't get what you're asking

@t3p3tony Hm so what would I do about the incredibly slow heating?

@t3p3tony If I don't have it on hand I'll just do it the previous way. Aliexpress takes at least 2 weeks to ship to me and I have everything else ready to go.

Edit: Sorry I completely misunderstood what you were saying. I googled around and couldn't find much either.

@djdemond 200W / 8.33A 24V heat bed, 350W / 14.6A 24V PSU

..Just realized, the mosfet is 12V. Or at least that's what the Amazon page says. But if I google for 24V mosfet I'm not getting any useful results.. Amazon page also claims it can handle 25A.

@djdemond Thank you! It works However heats extremely slow, which is possibly because I haven't run an autotune yet since using the previous 12v bed. I'm putting MGN12 rails on the Y axis tomorrow, so will install it properly and do the autotune etc then.

CTRL-in and Bed+/- is not the same thing. You can not connect a heated bed to CTRL-in. CTRL-in also does not have a polarity.

There is a DC IN+/-, Bed+/-, CTRL-In.

@djdemond

So just to confirm, I feed both the Bed VIN and Bed- to the Ctrl terminal? Are you sure VIN is needed?

Cheers

@djdemond Ah thanks!

So these have a 'ctrl in', a power+/- (dc in) and bed+/-

The ctrl in takes a 2 pin connector - do I use ctrl in for this?

I think I need a more detailed rundown if you can spare the time

From what you've said this is what I gather, but I'm still unsure about the ctrl in and BED- in particular

@djdemond said in 24v Heatbed with 12v everything else:

I'd like to throw in a second way, just in case the method outlined above doesn't suit you.

Get an external mosfet board (they are £5) . Optoisolated, they run from your bed heater output on the duet (12v is fine for this "signal") when the bed comes on the 12v signal switches the mosfet on the external board. Your 24v PSU is connected only to the external board, and through it the bed. I have a machine in this configuration.

Advantages:
Complete electrical isolation of 24v and 12v supplies.
No high current switching on your duet (I know compared to lesser boards they can do it but I like not switching so many amps on my most expensive component)

Disadvantages
None that I can think of (except spending £5).

These? https://www.amazon.com/gp/product/B06XY5HBFX/

I have four of them sitting in a box collecting dust.

I can think of one disadvantage, and that's having an extra board to account for when making an enclosure etc but that doesn't bother me.

@dc42 said in 24v Heatbed with 12v everything else:

That's not right.

Both PSU negative outputs go to the ground pin on the VIN terminal block (power GND). The + output of the 12V supply goes to the + pin on the VIN terminal block. The + output of the 24V supply goes to one end of the bed heater.

Thanks I think I understand now, one more time in the interest of not starting house fires:

@dc42 said in 24v Heatbed with 12v everything else:

You can connect your 24V bed heater between the +ve output from the PSU and the BED- pin of the bed heater terminal on the Duet. Leave the bed heater VIN terminal of the Duet unconnected. Connect the negative output of the 24V PSU to the negative VIN terminal on the Duet, along with the negative wire from the 12V PSU.

My parts finally arrived and I got around to trying this but I'm a bit confused - You say to plug BOTH the 12v and 24v psu into the power VIN on the DUET? It's not going to burst into flames is it?

I drew a quick diagram based on what you said, I want to be sure I have it right before I proceed. Could you confirm it's accurate?

If you're coming from Google DO NOT use this - it's wrong

I got it triggering correctly with Mode 1 but I need to set I1 with M558 also for it to work.

Unfortunately I still can't home, even after the changes adding S2.

@phaedrux said in Can't Home Z with a Z Probe installed:

I'm not sure if it matters, but you have your M574 command set to use a Z endstop currently.

Try changing that to M574 Z1 S2 ; Use zprobe and home to Z Min.

I say it may not matter because in the next few lines you specify the z probe in M558.

Your Homeall.g looks ok.

Your Homez.g won't work unless XY and already homed or you add S2 to your G1 move to get the probe in position.

Thanks for the help Unfortunately the same thing occurs.

By the way, does the reprap configurator have a setting for Mode 5? None of them have their mode numbers shown and it's 5 that works for mine. The others don't see it trigger. I keep having to manually set it after the fact.

I thought I uploaded the config.zip - if so what was in it that I shouldn't have linked it? Wifi p/w?

Well, I'm more or less at a loss.

That's odd somehow the public sharing turned off

<edited to remove the link>!

@phaedrux said in Can't Home Z with a Z Probe installed:

Can you post your config.g and your homing files?

Sure

https://drive.google.com/open?id=15q-ReiRuzfv0u6V4hmQRy1bwbsqbV75e

This is my config.json for reprapfirmware configurator if that helps

https://drive.google.com/open?id=12VJ0j6iLhLLwgAJG4DQbLxDPtQtFVlSx

X and Y are homed yet the error still occurs. What does it need?

I recently connected an EZABL and everything is working - when I put my finger under it, it's triggered.

However I can't home Z.

I read the guide here and specifically "Homing Z using a Z probe": https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareCartesianPrinter#Section_Homing_Z

It's illogical to me because it tells you to G30 to effectively home the Z using the probe but G30 can't run without Z homed. What do I do?

I tried using M574 to set Z end stop to use the probe but that didn't work either.

@dc42 said in 24v Heatbed with 12v everything else:

You can connect your 24V bed heater between the +ve output from the PSU and the BED- pin of the bed heater terminal on the Duet. Leave the bed heater VIN terminal of the Duet unconnected. Connect the negative output of the 24V PSU to the negative VIN terminal on the Duet, along with the negative wire from the 12V PSU.

Perfect, thank you once again!