Zortrax M200 Duet Conversion
-
Just an idea but why not simply cut the antenna trace on the ESP and tack on a coax pigtail that's terminated with a panel-mount SMA-RP connector? Then you could connect a cheap external antenna. If you keep the coax short any losses in the cable should easily be made up for with improved antenna gain.
-
I forget which, but a specific certification authority requires a built-in antenna for conformity. This is why.
-
Ah, that's a good point.
And yet the governing bodies seem to happily grant certification to Powerline Network Adapters that create massive amounts of broad-band interference I can hear on the HF bands for miles…but I digress.
I did some quick looking and at least here in the states the ESP seems to be available with both a ceramic antenna and u.FL connector already on-board that's FCC/CE certified:
http://store.hackaday.com/products/esp8266-07-module-with-u-fl-chip-antenna-fcc-ce-certified
-
Interesting! We made a few Duet WiFi prototypes using modified ESP-07 modules instead of the ESP-12F that we normally use. However, I have not seen any evidence anywhere else that the ESP-07 can be FCC certified.
-
It really would be awesome to be able to have an antenna mounted on the top or side or the printer.
This would allow the DuetWifi to be fitted to any type of printer with a metal cabinet.
I'm just waiting for my bootlace kit and crimper and I'll mount it all up.
Simple little things like needing 4mm standoffs instead of the Zortrax 3mm's are pain in the arse surprises, but I'm onto it and will print some temporary ones to get started.
I might start by mounting the board with the antenna facing the ventilation slots and see how that goes.
Do i really need the fan blowing on the underside of the board? Weren't the drivers tested with no cooling fan at all?
-
Bootlace kit and crimper turned up today, and makes nice neat work of putting the twin power supply and heat bed cables into the Duets terminal blocks.
School holidays in Oz, so I'd better put it all aside for a week or two or I'll get into trouble.
I'll be replacing the (prone to fail) ribbon cable with silicone insulated wires in braided sheath up to the hot end, and am wondering what sizes to go with.
I've got 24AWG which should be ample for the extruder stepper, fans, IR probe and thermocouple (or possibly PT100), but will it be heavy enough for the 24v heater element? Next size up I've got here is 18AWG which is quite a bit heavier.
-
From http://www.engineeringtoolbox.com/wire-gauges-d_419.html it looks to me that 24awg should be OK if your heater power is 40W or less.
-
Absolutely loving this engineer PA-09 crimping tool!
How good is this on 24AWG silicone wire…no more recycling/soldering old plugs etc!
-
Can anyone tell me what this plug into the extruder stepper motor is, and even better point me to a link where to buy them and a decent size bag of crimp pins?
I've been screwed by mouser/digikey etc before where I thought I was getting a bag of pins and they were price individually and the range of choices can be confusing at best.
-
I suggest you move the wire that goes to the centre tag on the end stop switch to the other outer tag if you can. It looks to me like a slide-on spade connector, so this should be easy to do. Then you will be using the common and NC switch contacts. At the Duet end of the cable, connect the two wires to the outer pins of the 3 pin endstop connector.
Correct on the limit switch.
Moving the center tab to the outside gives you normally closed (open when activated) operation.
At the Duet board end, if I use the 2 outer pins I'm across "GND" and "STP", and "3.3v" is left with no connection.
Just confirming that's the way you want it connected?
Another question would be how do I determine the pins for the stepper motors, or is it just a case of reversing 2 wires if it's traveling in the wrong direction?
It seems the stepper connection is a 6 way JST-PH, by the way.
-
Yes that's the correct end stop switch wiring.
For the motors, you need to pair the phase wires, but you can reverse the directions using the M569 commands in config.g if you don't want to touch the wiring.
-
Yes that's the correct end stop switch wiring.
For the motors, you need to pair the phase wires, but you can reverse the directions using the M569 commands in config.g if you don't want to touch the wiring.
Sorry…please explain "pair the phase wires" and how I would do that.
I have a multimeter handy if that will help me identify the pairs.
-
I assume your motors have 4 wires each. Find a pair of wires that have a few ohms of resistance between them. Those wires are one phase. The other pair of wires are the other phase - they will have the same resistance between them, and near infinite resistance between them and the first pair. Connect the two wires of one phase to the two pins near one end of the 4-pin connector on the Duet, and the other phase to the two pins near the other end.
The wires will probably be colour coded, and I suggest you use the same order of colours for all your motors.
HTH David
-
Cheers, I actually thought that was it, thanks for confirming.
They used all black wire, but I'll chase it visually and double check with the meter.
-
Moving along nicely, just waiting on silly little bits like standoffs, wire, fans, odds/sods.
Looking like a fairly straight forward swap with plenty of room in the electrical compartment.
I'll replace the K type thermocouple with an S3D PT100/daughter board I've got sitting here as the existing thermocouple only has short wires which I understand can't be extended, probably just in 2 wire configuration as I have the Molex plugs it's fitted with. UNLESS there's a compelling reason to use 4 wires on the PT100? Any suggestions on wire gauge for the sensor?
Existing extruder heater I'm assuming is 40w/24v, so 20AWG (even 22AWG) silicone wire with a microfit 3.0 plug will easily handle the current, so that's all good.
The heat bed is a bit of a bugger as Zortrax has some unique features there:
1. It uses nozzle contact pads to set nozzle height and level check. This feature is pretty good actually, and the only way it goes wrong is if the nozzle is very dirty with built up carbon. I wouldn't mind using it in conjunction with the IR sensor, but I'm guessing it's normally open then closed on contact with the pad, where the DuetWifi uses normally closed limit switching?
2. It unplugs at the back and sits on magnets so it can be lifted out on print completion. This is an awesome feature that I want to keep. Just so handy for removing prints without stressing the Z axis.
3. The PCB bed heater appears to be glued to the back of the ally part of the build plate. It doesn't want to come off, and I don't want to damage it. It appears to have a 100k thermistor (measuring 95k on my meter) which I'm assuming will plug straight up to the DuetWifi and has the wiring incorporated in the existing loom already. The bed heater measures 3.6 ohms, so I'm at 6-7 amps @ 24v? Easy work for the Duet then at half its rated current?
I was going to do away with the perfboard altogether and stick a sheet of Printbite straight onto the heated ally plate, but the plate is not very flat at all, which I guess is compensated by the fact that Zortrax software offers only raft printing.
What I'm thinking of doing is setting it all up with the IR sensor, and just using the raft option with S3D for now.
What would be nice in the future though would be a water jet cut cast ally plate 6-8mm thick with Printbite on top and a Keenovo heater in 240v, operated by an ACDC solid state relay. I'd get the plate cut will all the same mounting holes for the locating dowels, mounting magnets, etc so it would drop straight in. There's tonnes of room in the electrical compartment, and a big fan with plenty of ventilation, so that should be fine as well. I'd use a 4 pin 240v rated surface mount plug and make a new loom for the Keenovo mats power/thermistor.
Just thinking out aloud…any suggestions?
-
Sounds good! My thoughts:
1. If you will be using a plug/socket for the hot end, then I suggest you use a 4-wire configuration for the PT100 to guard against the contact resistance increasing. Just get a microfit 3.0 connector with a couple of extra ways, which is what I did when I upgraded to PT100.
2. Depending on how non-flat and flexible the existing bed is, and whether it would be possible and safe to use clips around the edge, you might get away with putting a sheet of 4mm glass on top and printing on that.
3. When you come to upgrade the bed, I advise against using a 240V heater if you want to disconnect the bed when the print has finished, because of the difficulty of making it safe. Your bed heater is only 160W so it is easily powered from 24V, and you already have a 24V PSU providing adequate power. You could order an EcoCast plate to your required size from http://www.aluminiumwarehouse.co.uk/cutting_calc.php and attach a 24V silicone heater to the underside and a thermistor or another PT100 in a hole at the edge. Make the bed plate a little larger than the heater and the print area to leave room for fixings.
My preferred arrangement for small to medium size print beds is glass clipped on top of aluminium, with or without a thin sheet of PEI attached to the top of the glass. The PEI is painted black on the underside for compatibility with the IR sensor. The glass can be unclipped from the bed plate when the print is finished.
-
Cheers David,
That ally cut place is a hot tip! Cheers for that.
A 240x240mm piece of 8mm thick "eco cast" (I'm assuming that's the precision flat one?) for 13 quid!!
Sold at that price, I'll drill and tap the thing myself.
I'll use the 4 wire method you showed in your blog for the PT100, but I'm thinking to solder it straight on without a plug at all for best results. It's not like I'll be expecting to change it frequently. I actually have 4 pin microfits as well but bugger it. Will 28AWG wires be OK over 1.5M?
Yeah…copy that on the AC heater. Bit too ambitious for my little printer, and Keenovo have an off the shelf 200x200 24v/200w that should give that little more kick. Especially under ally without the extra thick Zortrax perfboard to heat.
Can I just rely in the thermistor in the silicone heat mat?? Does the DuetWifi software allow me to calibrate the temperature reading to show the actual temperature I take on the build surface using a thermometer probe? I'd hoped to set the hotend temp the same way as well.
I'd prefer not to use glass and am keen to try the Printbite, as I print a lot with ABS up around the 260 deg mark, and am pretty much on the same page as Digital Dentist regarding ABS printing requirements (no offense meant). It seems to be get good reviews providing it's set up all level at the right nozzle height, and I'm pretty particular setting those up.
Bit of a pain sitting around waiting for little bits and pieces to arrive when you're all keen to fire it up…..
-
I use the thermistor built in to the silicone bed heater on my delta printer. It works, but it over-reads somewhat because it is close to the heater wires and not in good contact with the bed plate. So I have to set the temperature somewhat higher than I really want, but I have got used to that. Also it gives slightly strange heater tuning results because the system has 2 time constants instead of just one as the heater model assumes. A 3mm cartridge thermistor or PT100 set in a hole drilled into the edge of the plate would be more accurate.
If you intend to connect the PT100 sensor without using a connector, then a 2 wire connection should be adequate. To work out the effect of 3m of 28AWG wire, work out its resistance. One ohm of resistance gives a temperature error of 2.5C. If you use a 4-wire connection, the wiring resistance doesn't matter.
-
I use the thermistor built in to the silicone bed heater on my delta printer. It works, but it over-reads somewhat because it is close to the heater wires and not in good contact with the bed plate. So I have to set the temperature somewhat higher than I really want, but I have got used to that. Also it gives slightly strange heater tuning results because the system has 2 time constants instead of just one as the heater model assumes. A 3mm cartridge thermistor or PT100 set in a hole drilled into the edge of the plate would be more accurate.
If you intend to connect the PT100 sensor without using a connector, then a 2 wire connection should be adequate. To work out the effect of 3m of 28AWG wire, work out its resistance. One ohm of resistance gives a temperature error of 2.5C. If you use a 4-wire connection, the wiring resistance doesn't matter.
Thanks very much for that.
So a PT100 drilled into the plate it is then.
I'll use 4 wires both in the extruder and heat bed sensors.
I understand the single daughter board can run 2 PT100's? Is that correct?
I like the idea of accurate sensors on both the bed and extruder, might as well do it right.
I went looking for sensors with 4 wires standard.
Seems I can get longer ones in 3mm, which might be nice for the heat bed as it'd cover more area?
http://au.rs-online.com/web/p/platinum-resistance-temperature-sensors/7621143/
Seems this one only goes up to 200 degrees? Are all PT100's the same?
In 10mm long (for the extruder block) it seems I can only get 2 wire, so I'd need to solder wires on as per the DC42 blog?
https://littlebirdelectronics.com.au/products/pt100-temperature-sensor-probe
Here's an ebay one with wires long enough to go straight through to the board:
If anyone has links for what would be the very best option, please feel free to put them up.
-
Yes the PT100 daughter board supports 2 sensors.
