Hi David,
Is using the HW floating point beneficial to specific performance aspects at this point? Also, is this release including all of alpha 7 enhancements?

Dyze have a PT100 available, however it's not advertised. I still got one at the very beginning they were hesitant to sell because the PT100 insulation wasn't up to their spec limiting the temperature under 380°C. I don't use it that high anyway. I can say it works like a charm, the Duet, PT100 and Dyzend really is a winning combination.

I highly encourage anone printing materials at 350°C and under to get the PT100 and the daughterbaord. Just ask Dyze design directly, they are very helpful.

Temperature overshooting is likely since the hotend has a big heater. On 24v I used 20% power to tune. On 12v, don't go over 50% PWM.

@mb0:

any progress on this? i have a dyzend too and have trouble getting it running on 1.17dev6

I tested the 1.17dev6. It works, however the thermistor still has so much resistance at room temp that the reported temperature is still off and fluctuating. Moreover, the auto range ADC calibration means it sometimes initializes at 2-10°C at room temp or 15-30°C randomly. The room temperature fluctuation mens RRF forbids auto calibration. Dyze Design has a PT100 coming out very soon. I got it early and works well with the pt100 daughterboard. Now things work flawlessly.

@dc42:

I have just committed RRF version 1.17-dev1 on github. It includes changes to better support the Dyze thermistor, although I don't yet have one for testing with. See https://github.com/dc42/RepRapFirmware/blob/dev/WHATS_NEW for more details. Caution: I do minimal testing on dev builds.

Thank you David.
I will test the 1.17 dev tonight and report results with my Dyze 500°C thermistor.

I have a 12v PCB heatbed. If I fed it 24v directly it would run at about 15-16 amps. From a hardware perspective, would the board be able to sustain this load if I limited the pwm to 66% giving me an average 10A or is the peak current too high? I don't want to get a 24v pcb bed because they often have too high resistance values limiting the power output to measly 100-125w. I should probably invest in a silicone AC heat pad, but I don't seem to find reasonably priced SSR that can be trusted. Had a bad experience with ebay ones…

Thanks for your advice.

JasonW,
From your information: 0.3 A Z motors, I assume you have very high resistance and impedance motors. If this is the case, i.e. 12v rated motors, you will have very poor performance from them, especially in series. I see you have T8X2 leadscrews, and 1600 steps per mm on this setup. To move at 300 mm/min, the steppers, your motors would have to turn at 2.5 rps. Your motors will already have almost no torque when wired in series at this speed assuming these are high impedance motors. As an example, I have 30 Ohm resistance, and 37mH impedance motors on my machine. They don't run well without 24v power. I will swap them as soon as I can. You could probably use a Y cable fotr the Z motors and use jumpers in the second header to have them run in parallel like on ramps (adjust amperage accordingly). Could a hardware designer commnet on this?

Also, be careful if you run a 0.3 A motor at 1.8 A, they would probably become burning hot if kept energized.

Thanks dc42,
I've been told Dyze Design is working on a low thermal mass PT100 for their hotend. According to them, this should be available shortly. I will probably grab one if the price is reasonable. I already have the PT100 daughterboard ready! I agree the PT100 has desirable linear characteristics for wide range temperature measurements. The problem with thermistors is that they have to be specified for a narrower temperature range to be precise. The reasoning for the Dyze thermistor is still quite interesting regarding the precision and low response time around printing temperature. The only real flaw is the very low accuracy/high resistance at room temperature.
I'm not affiliated with them whatsoever, but it's still a very good hotend with a lot of desirable characteristics.

I will chime in on this issue. I own a Dyze 500°C thermistor. Without a parallel resistor it gives me the disconnected fault. The real resistance at 25°C is really around 4.5MOhm and much higher at 20°C. The board works with a parallel 1 MOhm resistor. I actually made a wiring extension with parallel Dupont connector to be able to experiment with different resistors. it's not perfect, but the measurement error gets very small at 200-250°C which is my preferred printing temperature. If we had support for steinhart-hart parameters (on FW 1.17) I could probably make it read room temperature accurately, but right now, I have to live with 45-50°C readings at 20°C (from the parallel resistance error).

I really wish there would be a firmware workaround to disregard the "disconnected" state for these thermistors at room temp.

I fountd the culprit: the right formulation was S0 to end the calibration routine. I changed my file to the form in the Wiki:

M561 ; clear any existing bed transform
G30 P0 X10 Y10 Z-99999 ; define 4 points in a clockwise direction around the bed, starting near (0,0)
G30 P1 X10 Y190 Z-99999
G30 P2 X190 Y190 Z-99999
G30 P3 X190 Y10 Z-99999
G30 P4 X100 Y100 Z-99999 S0 ; finally probe bed centre, and calculate compensation
G1 X0 Y0 F5000 ; move the head to the corner (optional)