Dc42 Sensor Board proximity issues Kapton

Hi

In the past i only use a permanent Print plate but no it is broken. So I go back to a glass plate with kapton tape.

I wanted to home Z with my dual noozle proximity board, but the axis didn't stop, and the hotend crashed to the bed. I the probe didn't recognize the kapton and glas plate.The probe value don´t raise up to over 500, it stay´s at 1-3.

My wiring is only 3-wires with the probe...
In config.g us M558 P1

Any hints?

Edited 2 time(s). Last edit at 10/04/2014 03:54AM by muggi.

Muggi, when you were using the permanent print plate, what X height were you using in your G31 command? Also, when the nozzle is just touching the bed, how high above the edge of the bed is the bottom edge of the sensor board?

I suspect one of the following:

1. The board is mounted too high above the nozzle. The edge of the board should be between 1mm and 2mm above the tip of the nozzle.

2. The board is not perpendicular to the bed.

3. The board is triggering at too low a height. This could be because the phototransistor or one of the IR LEDs has been bent. A few boards in the first batch I shipped also had low trigger heights that I now consider unacceptable.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Hi David,

on my permantent print aluminium plate i have G31 P500 Z1.65 in my config.g.
So i think the mount point of the sensor board (your modded Fan Duct) is ok.
The board is perpendicular.
Only if i tiltit (appjaws dual noozle mount) closer to the bed, the probe works on kapton.
I will check if the led´s or the sensor is bend now.

Quote
dc42
Muggi, when you were using the permanent print plate, what X height were you using in your G31 command? Also, when the nozzle is just touching the bed, how high above the edge of the bed is the bottom edge of the sensor board?

I suspect one of the following:

1. The board is mounted too high above the nozzle. The edge of the board should be between 1mm and 2mm above the tip of the nozzle.

2. The board is not perpendicular to the bed.

3. The board is triggering at too low a height. This could be because the phototransistor or one of the IR LEDs has been bent. A few boards in the first batch I shipped also had low trigger heights that I now consider unacceptable.

Hi David,

so i checked if an LED or the phototransistor is bend, but all are on a good position. So why i cant get no readings on my glas plate with kapton?

If i use a hite paper on the plate the readings are ok and about 1.6 mm above the bed.

Muggi, can you confirm that when you have the sensor over white tape or plain glass or aluminium (any of those will do), as the sensor approaches the surface, the reading jumps from about 0 to about 465, and then jumps to 535 (and the red LED turns on) when it is a little closer? I want to confirm that the sensor is working in differential mode. If it jumps directly from 0 to 535, then it is working in simple modulated mode instead, which would explain the problem.

Best regards - David

Edited 1 time(s). Last edit at 10/04/2014 11:37AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Hi David,


yes i can confirm that it goes from
1-3 (more than 1.7mm between bed and noozle) to
465(1.7-1.6 mm between bed and noozle) and then
535(closer then 1.6mm between bed and noozle).

Edited 2 time(s). Last edit at 10/04/2014 02:19PM by muggi.

Hi,

any hints?

It's possible that you have the board mounted too high on the hot end. How much higher is the bottom edge of the board than the tip of the nozzle?

Another possibility is that you have an out-of-tolerance board (there were a few of those in the first batch). If that is the case, then I will replace the board. The best way to check this is first to print the calibration piece here [github.com]. Then power down the Duet and remove the board from the hot end but keep at least the 4-pin connector connected. Place the calibration piece on a piece of plain glass (you can use the reverse side of the bed plate). Power up the Duet using USB power only, taking care that the board cannot short against anything. Hold the board with its lower on the stepped edge of the calibration piece and the IR sensors over the glass, so that the board is at right angles to the glass. Then you can see which is the highest step for which the red LED illuminates. The steps go from 2.5mm to 3.75mm, in 0.25mm steps.

Edited 3 time(s). Last edit at 10/05/2014 12:59PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].