Urgent help - Mini IR sensor with DUET 0.6



  • I am using DUET 0.6 boards (from Reprap ltd) in 2-3 printers. Previously I was using 4 pin old IR sensor from Reprap ltd.

    3 months back, I purchased 3 pin mini IR sensor and started using it. Working without any issues. Differences are quite big.

    Last 10 days I was building one CoreXY with 300x300x300. I updated Reprap firmware with 1.18.1. And used the configurator to create config files for CoreXY setup.

    All the movements are ok. But I faced a weird issue with the mini IR sensor. When I used it for homing only Z axis, when the bed comes near the sensor, it is showing the value of 465, but it is not homing. I tried with different parameters, different settings, different wires etc. It is not homing.

    Then I changed the same sensor to other Cartesian machine (same DUET 0.6 board), it is working.

    Only, it is not working with this CoreXY. Then, I used old 4 pin IR sensor with this CoreXY, it is working, but not that accurate.

    Please help me in sorting out this mini IR sensor issue. (I have to deliver the machine to the client by tomorrow).

    The following are the lines from config file (I am not sure how to attach a file here).

    ; Endstops
    M574 Z0 S0 ; Define active low and unused microswitches
    M574 X2 Y1 S1 ; Define active high microswitches
    M558 P1 X0 Y0 Z1 ; H5 F120 T6000 Set Z probe type to unmodulated, the axes for which it is used and the probe + travel speeds
    G31 P500 Z1.0 ; Set Z probe trigger value, offset and trigger height X25 Y0
    M557 X15:285 Y15:285 S20 ; Define mesh grid

    I created one help topic in forums.reprap.com in which I have attached the config and homing files.

    http://forums.reprap.org/read.php?416,775381

    Thanks



  • There's probably a better solution but you could change threshold in G31 to P450.



  • I checked with 460 also, not working. What is the other solution?



  • That would be for David to chime in with its his sensor. My personal preference is for nozzle contact sensors but it sounds as if the IR sensor you have might not be working normally.



  • There are two receivers on the board. in analog mode the first one will give an output of 465, this will cause the z motion to slow down. What it is looking for is the second output at about 535. This is the one that should trigger the endstop.

    You should be able to trigger these with your hand and see the output with an M119


  • administrators

    Your IR sensor will output about 465 which it is approaching trigger height, and about 535 at/below trigger height. At the same time as producing a reading of 535, the red LED on the sensor will turn on. If you don't get 535 even with the nozzle touching the bed, this usually means you have mounted the sensor too high on the hot end. The bottom of the sensor should be no more than 2mm higher than the tip of the nozzle, and preferably about 1.5mm.



  • Ok. The distance between hot end and sensor is around 1-1.5mm only.

    In this case, after homing X and Y, I tried to trigger the Z sensor manually. The value of 465 comes, then it triggers at 535. But it is not showing as 'Home Z' is done. In DWC, the 'Home Z' is still in Yellow color. Also, the Z axis is still moving without stopping.

    Any coding issue? I am getting Red light glowing properly when I do manual triggering. Even when the machine is switched on the red light is blinking for 4 times.

    Please check the coding which is attached in the link given :
    http://forums.reprap.org/read.php?416,775381


  • administrators

    Please post your homez.g file here. The reprap.org site is too slow to be usable at present and is giving bad gateway errors again.



  • As suggested by DjDemonD, I changed the value to 450. Luckily it started triggering. But, here and there it is giving errors. I changed the values to 460, 470, 480. At 480 it is not triggering. So, now keeping at 470 only. But still some issues.

    Here is my homez.g:
    ; homez.g
    ; called to home the Z axis
    ;
    ; generated by RepRapFirmware Configuration Tool on Tue Jun 27 2017 17:39:17 GMT+0530 (India Standard Time)

    ; Lift Z relatively to current position
    G91
    G1 Z5 F6000

    ; Back to absolute positioning
    G90

    ; Go to first bed probe point and home the Z axis
    G1 X285 Y15 F6000

    G30

    G1 Z0 F200
    ; Uncomment the following lines to lift Z after probing
    ;G91
    ;G1 Z5 F100
    ;G90

    And here is my config.g file:
    ; Configuration file for Duet 0.6 (firmware version 1.17)
    ; executed by the firmware on start-up
    ;
    ; generated by RepRapFirmware Configuration Tool on Tue Jun 27 2017 17:39:17 GMT+0530 (India Standard Time)

    ; General preferences
    M111 S0 ; Debugging off
    G21 ; Work in millimetres
    G90 ; Send absolute coordinates…
    M83 ; ...but relative extruder moves
    M555 P2 ; Set firmware compatibility to look like Marlin

    M667 S1 ; Select CoreXY mode
    M208 X0 Y0 Z0 S1 ; Set axis minima
    M208 X300 Y300 Z300 S0 ; Set axis maxima

    ; Endstops
    M574 Z0 S0 ; Define active low and unused microswitches
    M574 X2 Y1 S1 ; Define active high microswitches
    M558 P1 X0 Y0 Z1 ; H5 F120 T6000 Set Z probe type to unmodulated, the axes for which it is used and the probe + travel speeds
    G31 P500 X25 Y0 Z1.2 ; Set Z probe trigger value, offset and trigger height
    M557 X15:285 Y15:285 S20 ; Define mesh grid

    ; Drives
    M569 P0 S1 ; Drive 0 goes forwards
    M569 P1 S1 ; Drive 1 goes forwards
    M569 P2 S0 ; Drive 2 goes forwards
    M569 P3 S1 ; Drive 3 goes forwards
    M92 X80 Y80 Z400 E420 ; Set steps per mm
    M566 X900 Y900 Z12 E120 ; Set maximum instantaneous speed changes (mm/min)
    M203 X15000 Y15000 Z180 E3600 ; Set maximum speeds (mm/min) M203 X6000 Y6000 Z180 E1200
    M201 X800 Y800 Z15 E1000 ; Set accelerations (mm/s^2) M201 X500 Y20 Z250 E250
    M906 X1000 Y1000 Z1600 E800 I30 ; Set motor currents (mA) and motor idle factor in per cent
    M84 S30 ; Set idle timeout

    ; Heaters
    M143 S300 ; Set maximum heater temperature to 300C
    ;M305 P0 T100000 B3950 C0 R4700 ; Set thermistor + ADC parameters for heater 0
    M305 P1 T100000 B4725 C0 R4700 ; Set thermistor + ADC parameters for heater 1

    ; Tools
    M563 P0 D0 H1 ; Define tool 0
    G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
    G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0C

    ; Network
    M550 PGaruda3d + ; Set machine name
    M540 PBE:EF:DE:AD:FE:ED ; Set MAC address
    M552 P192.168.0.54 S1 ; Enable network and set IP address
    M553 P255.255.255.0 ; Set netmask
    M554 P192.168.0.1 ; Set gateway
    M586 P0 S1 ; Enable HTTP
    M586 P1 S0 ; Disable FTP
    M586 P2 S0 ; Disable Telnet

    ; Fans
    M106 P0 S0.3 I0 F500 H-1 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off

    ; Custom settings are not configured

    ; Miscellaneous
    T0 ; Select first tool


  • administrators

    I can't see anything in your homez.g or config.g that would cause this.

    Please try raising the nozzle some way off the bed. Check that when you hold a piece of paper under the nozzle, the red LED comes on and the Z probe reading jumps to about 535. Then execute G30 to start a single Z probe. When you hold the paper under the nozzle so that the LED comes on, the probing move should stop.

    If that works, then Z homing should work if you can get the probe to trigger before it touches the bed. What bed surface are you using? If it is transparent to IR (e.g. glass, PEI, or PrintBite), how thick it is, what is the surface below it?



  • Thanks for your kind support. As I told, I tried with the 470 value. It is working now. Beyond that it is not triggering (as suggested value of 500 is not working).

    Also, I faced another issue :
    M558 P1 X0 Y0 Z1 H5 F120 T6000 Set Z probe type to unmodulated, the axes for which it is used and the probe + travel speeds.
    M557 X15:285 Y15:285 S20 ; Define mesh grid

    If I give the above command as it is in config.g, Auto bed compensation is not happening.
    So, that I am giving like this:

    M558 P1 X0 Y0 Z1 ;H5 F120 T6000 Set Z probe type to unmodulated, the axes for which it is used and the probe + travel speeds. - Here I am disabling after H5
    ;M557 X15:285 Y15:285 S20 - This line also disabled.

    After this Auto bed compensation is working.


  • administrators

    You won't get a very accurate trigger height with a threshold of 470. You didn't answer my question about the bed surface and backing.

    I don't understand why modifying/disabling those commands would affect G32 bed compensation. I suspect you made another change too.



  • Sorry, sir. I am using white masking tape in the top of the glass.

    Now when I checked it again, it is working only with the value of 460.
    At the value of 460, when I move the paper against the sensor, Z probe value is changing to 465 and becomes red (in DWC). Even at Z homing, if I move the paper, the value changes to 465, becomes red and Z stops.

    Whatever other value I use like 470, 480, 500, even 505, for all these values, Z probe value is showing as 465,466 - only green indication is coming on Z probe value (in DWC). The red indication is not at all coming.

    As of now using white masking tape on top of plain window glass.


  • administrators

    Please verify that with the tip of the nozzle touching the white masking tape, the distance between the bottom edge of the sensor and the bed is no more than 2mm. If that's the case, and you are only getting a reading of about 465 and the red LED doesn't illuminate, ask your supplier for a replacement IR sensor. If you bought it direct from me, please provide the invoice number and delivery postcode if you can.



  • I verified the distance. It is below 2mm only. Red LED in the IR sensor is glowing. But, the red indication in Z probe value in DWC is not coming. It shows only Green indication (for values more than 460). For value of 460, the red indication is coming.

    I bought it from DUET3d 6 months ago. But, started using last month only


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