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If you have a Precision Piezo Z-Probe and want to connect it to your duet wifi/ethernet board here's how to do it. Tuning and other aspects of the probe's operation are dealt with in the manuals at http://www.precisionpiezo.co.uk/documents

Electrical connection:
The Piezo20 module or Universal Z-Probe Kit PCB comes with a standard DuPont 3 pin endstop cable attached with correct wiring at the piezo pcb. The other end has three wires red (VCC), black (GND) and green/blue (SIG/TRG). A 4 pin DuPont connector housing is supplied.

Insert the red wire at one end of this housing, ensure the crimp is inserted so the spring clip retains it in the housing. Leave a gap of one pin, then connect black, then green/blue. Insert the plug into the duet z probe connector with the red wire end facing toward the long expansion socket and the green/blue SIG wire facing towards the end of the duet board with the LEDs and sd card slot.

Config.g

You need to define a probe there are two options:
Analogue:
This enables you to adjust the fine sensitivity of the probe on the fly, the coarse sensitivity is adjusted from the pcb. If using a Piezo20 module the signal must be NO (active high) and therefore use the I0 parameter. If using universal kit PCB you can set up the PCB with a NO - active high (I0) or NC - active low (I1) signal. It's your choice but NC -active low offers failsafe operation.

Add
M558 P1 I0(or I1) R0.4 F300 X0 Y0 Z0
(analogue mode, NO/NC, delay, speed, not used as axis endstop)

And

G31 X0 Y0 Z-0.1 P600
(X, Y, Z offsets, sensitivity/threshold)

To reduce mechanical noise from the frame or axis vibration, the R parameter is the delay before probing in seconds, set a longer delay if the probe triggers before contacting the bed.

Probing speed F parameter (in mm/min). A value from 300-420 is recommended. Slower can give more accuracy but too slow may not trigger, as the probe generates a signal on a change (compression or flexing in the piezo disc.

The z probe analogue value is from 0 to 1000. If you get a lot of false triggering increase this value, a firmer bed contact will be needed to trigger. This value can be seen on Duet Web Control in the "z-probe" box. It is normal for this value to bounce around during head movement and printing moves, its only required for it to be stable just before and during probing dives.

Digital:
which is simpler and works as it would on an 8 bit board.

Add
M558 P5 I0( or I1) R0. 4 F300 X0 Y0 Z0
(digital mode, NO/NC, delay, speed, not used as axis endstop)

and
G31 X0 Y0 Z-0.1 P100
(X, Y, Z offsets, debounce interval)

The debounce interval in ms smoothes the signal.

Please note as of RRF version 1.20 you can use M558 P8 instead (other parameters are the same) which is a digital probe but without filtering or smoothing of the signal. This increases accuracy, as it takes less time to react to a trigger.

The Z offset accounts for the compliance in the sensor and is usually -0.1mm as effectively the trigger point is just below the bed (this is opposite with inductive/IR sensors which trigger above the bed). If you have to babystep your first layer lower by 0.1mm, for example, then reverse the sign and add it to your G31 offset or vice versa if you have to babystep higher subtract the value from G31. Example, G31 Z-0.1 is set in config.g, probe/level/home/calibrate then print, if you babystep up 0.1mm then subtract 0.1mm from G31 Z change the value in config.g, power cycle/reset the machine, when your print finishes and you are ready for consistent first layers from now on.

Okay so forget about colours of wires when wiring stepper motors. Every different brand of motor has different colour wiring there is no standard.

This is about understanding how they work. Once you do it will seem simple. They have two sets of coils inside (that's why they're called bipolar). Two of the wires go to one coil, the other two wires go to the other coil.

On most printer controllers, and duet wifi is the same the motor plug has 4 pins. The two pins on one side pins 1,2 go to one coil, the other two pins 3,4 go to the other coil. What you need to do is determine which of your 4 wires from your motor are a coil pair. So get multimeter on ohms/resistance and measure between the motor wires. Two wires will have some resistance between them, they are one pair, the other two wires are the other pair. Now you know how to wire it one pair to pins 1,2 and the other to pins 3,4.

Write down the colours which form the pairs as you might have more of the same brand motors and they can all be wired the same way.

Motor might turn in the wrong direction when you ask motor to move, but its an easy fix if the motor goes the wrong way, TURN THE POWER OFF, then turn the motor plug the other way around, this swaps the pairs over and now the motor turns the other way. You can change the motor direction in firmware, but never unplug or work on motor plugs or wiring with power on, it can destroy the motor driver chips, which is an especially irritating and expensive mistake to make on duetwifi as you can't just plug new ones in.

Yep those are the things. If you have a 1 PSU system and your bed is below the 18A suggested limit, then they are probably an extra bit of kit you don't need. But a 2 PSU system is easily setup using one of these. Plus you get the highest current part of the system off the duet board - not a bad idea really.

Those smaller ones will work for most application they do make an even larger one

But I did buy one of these, they are massive could probably handle 50A+

I have these big red emergency off switches on all my printers.

http://m.ebay.co.uk/itm/Emergency-stop-button-station-twist-to-release-CE-1-N-C-contact-PT-A1-/231146690965?nav=SEARCH

They are only single pole so for mains heat beds in an error state caution is still advised.

I also with a bit of help from David and a few other on reprap came up with a simple smoke power shutoff.

http://forums.reprap.org/read.php?392,578686

It's not been extensively tested to determine if it will shut off the power before a fire begins, but it does latch in an off state when smoke is detected and requires manually resetting once the fault has been cleared, I expect it would work best in an enclosure. No false triggers yet after over a year in use, no genuine one either thankfully. It's obviously independent of the controller, and fairly simple.

What I have started using on my new printer is a plug-in rcd (ground fault device) right next to the machine. I can hit the test button as an emergency stop or general off switch, it should protect me against a mains heat bed problem and its double pole so shuts off the power to the device completely.

@Agniusm:

@DjDemonD:

Plasticmetal- hmm yes i don't know why I posted that, must have been tired and looking at the wrong message. Show us a photo of your setup especially where the piezo is mounted. First thing to try is reversing the polarity of the piezo disc by flipping the plug around at the piezo pcb.

Agniusm - make sure the red led is on by tuning vr2 (or the single pot if its a later revision), then use I1 in M558 (which is active low, the default mode for the latest piezo boards). It should be - red LED on until the piezo is bent/squeezed then it changes to blue for 0.25 seconds. There's nothing wrong with using Z1 (although it's technically deprecated after 1.19) but if homing with a piezo probe you are better off homing x and y then using G30. You might need to change threshold in G31 P…. or consider using M558 P5 mode or P8 mode which I find less difficult to work with.

I have red light and when i touch the nozzle blue comes on without any force. When i home Z it digs into the bed, and stays there. It should just touch it and back off as i understand which is not happening.

I now tried M558 P1, P5 and P8
P8 brings manual leveling dialog in web interface and P1 and P5 acts the same.
I have more recent board with 1 pot and if i adjust it to sensitive it triggers on the start with error message

Okay so on your duet web control, when you tap the sensor and the light changes from red to blue with light force, what does the z-probe box say? It should say 0 (if on p5/p8) then 1000 when triggered, or if on P1 it might read something around 200-300 open and then rise to 700+ triggered.

P8 bringing up the manual levelling dialogue in DWC suggests a software or config problem as that should not happen. Are you using the z-probe connector on the duet? and have you verified the wiring is correct?

Please also do this polarity verification test "push up on the (cold) nozzle (not tap) see what happens, then release the pressure. If it triggers on push it's correct if it triggers on release the polarity is reversed of the piezo disc.

Yes by using a 24v to 12v buck converter. Or by buying 24v heater cartridges.

A 12v cartridge run at 24v produces 4 times the power. That's why you can't achieve this by setting PWM to 50% (as that's not actually 50% lower power) or even PWM 25% which is 50% lower power output because you're forcing the cartridge to run at 120w (when it was 30w at 12v) which is not good from a safety point of view.

As a real ghetto workaround you could run two 12v cartridges in series, but you need to do something with the second one - maybe there is something else that needs usefully heating? More likely to just be a fire risk, having a hot thing flapping about doing nothing.

Initially I used a buck converter as I had 12v fans and heaters, but now I stock 24v ones so I use 24v ones its much easier.

I can understand why different methods of estimating print time remaining all have their individual validity, but given that they all change/converge as the print progresses and are viewed, certainly by me, as fairly much rough guesses anyway, why not just average the three methods and display one print time remaining saving screen real-estate and potential confusion?

Okay so were always answering questions about fans and voltages, buck converters and PWM.

Not a big problem but would it be possible in future revisions of the board to have fans independently powered by the voltage choice of the user. I appreciate having a jumper block for 5v, 12v (and a reg) and Vin (often 24v) would be quite cumbersome, but how about some sort of fan control IC which would allow fans voltage to be set from software?

It would allow the use of the varied fans that people have lying around (also bear in mind not all fans are easily available in all voltages), think Noctua (very popular), but not easy to get in 24v. Might also mean less space taken up on the board if there exists some chip that can do 5v, 12 and Vin rails and PWM multiple fan outputs.

Thoughts?

My experience with this has been to measure temp at the nozzle with an accurate device like a K type thermocouple. If it's correct then it's a mechanical problem. Check extruder gear isn't clogged.

If it's tough to push filament through by hand the nozzle may be partially blocked. Cleaning with microdrills, burning it out with a blowtorch for a good long while these work. But nozzles are often cheap swap it out. Make sure when you tighten the new nozzle to the heatbreak you do it as hot as your setup allows 270 degC or so any loose fit between nozzle and heatbreak will cause problems.

Make sure the heatbreak is clean and be careful not to scratch the inside surface with any tools. Quality all metal heat breaks only work if highly polished or coated in some way. Ptfe lined ones are more tolerant, but make sure the ptfe isn't old and degraded which it does become even at 250 deg C max over long periods.

Also I'd recommend using heatsink compound between heatbreak and heatsink, nothing between heatbreak and heater block and copper grease between the nozzle and heater block.

+1 for that, some sort of multifan add on module would be quite popular, something with Vin, 12v and 5v available, maybe even bus connected to the new duet system, so that you could attach maybe 6 fans at whichever voltage you wanted. Maybe native support for RPM monitoring for failed hotend fan etc..

I can help with some part of this in that we sell PT1000's. You can connect directly a 2 wire PT1000 to a thermistor input. Once the firmware knows its a PT1000 not a thermistor then it provides a reasonably accurate temperature reading. However the 10bit DAC cannot resolve more than +/-2 Degrees C so for extremely precise control the much more accurate amplifier in the daughterboard coupled with PT100 is better.

PT1000s are not as affected by interference as they operate over a wider range of resistances, with less amplification.

No its okay Tony I must have been typing incorrect search terms.

It would be very nice to be able to arrange the gcode files list by date, name etc.. to assist with finding the file you want to print if you come back to print it again. At present it can be a very long list to search through to find the file, in alphabetical order by filename, especially if you cant remember the name!

Also I'd second requests to be able to backup the SD card or just the system folder as a zip or similar.

So all back up and running.

Just to mention that despite the widespread damage the PT100 daughterboard survived.

Just as a tangeant to this, why not have two macros, each one has the complete M558, G31 commands, then just run whichever macro for whichever setup you want?

So I've got a delta with a lot of cables:
2 Cat 5 to the smart effector
Drive cable to the Nimble extruder
Water cooling hoses.

I've done a quick video to show how the cables move around.

https://youtu.be/JPLFe7PQp98

Since my electronics are at the base of the machine, I loop the electronics and drive cable up and over and support them with a quality keychain retractor. The water cooling hoses just kind of coil up without any real drama all by themselves. I've had only one issue with wire breaks but I did do away with the 2x3 molex connector on the smart effector and just use Dupont 2 pins (24v hotend), and have had fewer issues since. I can move anywhere in the build volume and even position outside the (over-sized) bed area to do filament purges.

I've tried flying extruder and whilst it probably beats bowden (although the margin is smaller since capricorn and pressure advance came along) it does add some mass (indirectly) and inertia and requires slightly smoother XY jerk/accel. Remote extruder wins for me. But the drive cable (and my water hoses) do the same thing they create "indirect" XY inertia, as such recent experimentation has seen me go back to 1000 accel for XY and 500 jerk.

Yes using it the way elmoret suggested works great and I have done so many times.

Do not PWM it down from 24v. Most people would set 50% which is actually still 2x the max power, it would need to be 25% PWM max to get a rough equivalent, but even then its just 25% duty cycle of 24v ON, 0v, 24v On, 0v etc... You're still running your heater at 4 times its rated power output just only for 25% of the time, assuming nothing (like a mosfet) fails and runs the heater at 4 times power for the few minutes/seconds it would take to melt and/or catch fire.

I take your point @pro3d that if you want a simple controller, then marlin running on one of the plethora of cheap controllers that exist now, is probably a simpler and cheaper solution. I have one machine still running on arduino/ramps and marlin (3 year old version at that) because it just works. I agree to some extent that if I was an OEM, it might be easier to just send a hex file to customers when I updated the firmware on their machines. It seems to work for Creality etc.

Duet is a product aimed at those who want to utilise a broad array of very useful features but not everyone needs them all (or even most of them), if the machine they are operating is fairly simple. I have a cr10 and wouldn't bother with a duet upgrade as it works out of the box. However my delta is complex and my corexy a platform for developing sensors, so the feature rich landscape with duet works there. I can't see an easy way to have a simple mode and an advanced mode, but maybe this is the way to go.

Hi Jannis.

If you want I will send it on to you. I have done this in the past for people. Please feel free to PM me, or contact me via Precision Piezo website (see my sig). Please mark your email FAO Simon, as Idris my colleague is handing all the day to day operations.