Heatbed Automatically Starting?

Shiven

1. With the bed heater disconnected, does the bed heat LED turn on as soon as you apply VIN power to the board?
No, Light doesn't come on at all, unless heat bed is connected

2. Do you have the bed heater connected directly to the bed heater output terminals, or some other arrangement?
Connected directly to the output terminals.

3. What sort of bed heater are you using, and what VIN voltage are you using?
I believe it is a prusa heatbed mk 2. Red, standard aluminium(?) platter. Quite old (6 years?). VIN voltage is 12V off a standard ATX PSU (quite literally pulled from my old ramps board into my new Duet Wifi.

4. How long have you had the board? Your supplier may be prepared to replace it under warranty.
4 Days, though i imported it from England so its going to be difficult to do any sort of swap over. (I am Australian)

Thanks for all the help thus far, seems like i'm looking at doing a changeover.

Shiven

Scratch this entire post, apologies, my board appears to be playing fine now. I plugged the connectors back in (after removing in the first step) and its not going crazy anymore.

I don't have a reason why, but its working. Apologies on that.

dc42

@Shiven:

1. With the bed heater disconnected, does the bed heat LED turn on as soon as you apply VIN power to the board?
No, Light doesn't come on at all, unless heat bed is connected

That indicates a short between one of your bed heater connections and ground. If the problem was the mosfet on the Duet, the LED would be lit even without the bed heater connected.

paralepsis

Hi,

I'm having the same problem that this person originally reported. I have done a modest amount of printing, and I am accustomed to the heated bed staying cold on start, with no activity on bed heat LED until I kick things into gear. Furthermore, that light would rapidly flash as the PWM did it's thing. Now, I get instant-on, and "M140 S0" has no impact – just keeps on heating. Temperature readings appear correct, at least :)?

Answering your questions:
1. With the bed heater disconnected, does the bed heat LED turn on as soon as you apply VIN power to the board?
Yes.

2. Do you have the bed heater connected directly to the bed heater output terminals, or some other arrangement?
Yes. There is an inline thermal fuse, but thus far hasn't been tripped.

3. What sort of bed heater are you using, and what VIN voltage are you using?

I'm using a 24V MK2A 300x300 bed:
TriGorilla 3D Printer MK2A Aluminum Heatbed Hot Plate Power Supply 24V RAMPS 1.4 For RepRap Prusa Mendel 3003003mm
VIN is 24V from a Meanwell PS (MSP-600-24).

4. How long have you had the board? Your supplier may be prepared to replace it under warranty.
April 2017 from Filastruder.

Configuration below. Thanks for all your help.

Rob

; Configuration file for Duet WiFi (firmware version 1.19.2)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool on Thu Jul 20 2017 18:24:16 GMT-0500 (CDT)

; 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 X320 Y285 Z335 S0 ; Set axis maxima

; Endstops
M574 X1 Y2 Z0 S0 ; Define active low and unused microswitches (Z1 if using that endstop!)

; Drives
M569 P0 S0 ; Drive 0 (X) goes backwards (1.19)
M569 P1 S0 ; Drive 1 (Y) goes backwards (1.19)
M569 P2 S0 ; Drive 2 (Z) goes backwards
M569 P3 S1 ; Drive 3 goes forwards
M569 P4 S0 ; Drive 4 (3rd Z) goes backwards

M584 X0 Y1 Z2:4 E3 ; Map drives (as above)

M350 X16 Y16 Z16 E16 I1 ; Configure microstepping with interpolation
M92 X100 Y100 Z400 E837 ; Set steps per mm
M566 X900 Y900 Z12 E120 ; Set maximum instantaneous speed changes (mm/min)
M203 X7200 Y7200 Z365 E1200 ; Set maximum speeds (mm/min)
M201 X500 Y500 Z250 E300 ; Set accelerations (mm/s^2)
M906 X1000 Y1000 Z1000 E800 I30 ; Set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout

; Heaters
M143 S260 ; Set maximum heater temperature to 260C

M307 H0 A67.9 C260.8 D2.5 S0.80 B0 ; Set PID controls with new (M307) parameters, calculated for 80% PWM max.
M307 H1 A337.6 C147.4 D4.5 S1.00 B0 ; Set PID controls with new (M307) paramters, calculated for 100% PWM and 250C.
M305 P0 T100000 B4138 C0 R4700 L0 H0 ; Set thermistor + ADC parameters for heater 0 (bed)
M305 P1 T100000 B4725 C7.06e-8 R4700 L0 H0 ; Set thermistor + ADC parameters for heater 1 (hotend) (from E3D documentation for RepRap > 1.17)

; Tools
M563 P0 D0 H1 F0; Define tool 0 to be D (drive) 0, H (heater) 1, and F (active cooling fan) 1
G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0C

; BL Touch
M307 H3 A-1 C-1 D-1              ; reserve pin 8 (Heater 3 PWM) for BL Touch
M558 P5 X0 Y0 Z1 H4 F200 T800 R1 ; type 5, use for Z, Feed rate 200 mm/min, 
                                 ; dive Height 4mm, Travel speed 800 mm/min, wait 1s (R) before dive
G31 X-8 Y-41 Z1.46 C0 S0 P25\.    ; this Z has me using a +0.15mm Z offset in Slic3r for PETG
M557 X30:240 Y20:240 S42         ; S35 is 7 points in each axis. S42 is 6 in each axis.
M280 P3 S160 I1                  ; reset probe error state
M280 P3 S90 I1                   ; retract

; Network
M550 PBigBoy ; Set machine name
;M552 S0 ; Disable network
M552 S1 ; Enable network
M552 P192.168.1.120  ; Set the IP address
M553 P255.255.255.0  ; Set netmask (Subnet Mask)
M554 P192.168.1.254  ; Set the gateway (Default Gateway)
;
; Access point is configured manually via M587 by the user, info stored in ESP8266 (not config files)
; M586 P0 S1 ; Enable HTTP
; M586 P1 S0 ; Disable FTP
; M586 P2 S0 ; Disable Telnet

; Fans
; NOTE: P0 is set (above) to be active cooling for tool 0 (which is also default).
; NOTE: P1 is thermostatically controlled and left alone by slicer (I hope).
;
M106 P1 S1 I0 F500 H1 T45; Set fan 1 (hotend) value, PWM signal inversion and frequency. Thermostatic control is turned on
M106 P0 S1 I0 F500 H-1; Set fan 0 (active cool) value, PWM signal inversion and frequency. Thermostatic control is turned off
; M106 P2 S1 I0 F500 H1 T45 ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned on

; Custom settings are not configured

dc42

It sounds like either the bed heater mosfet or the driver has failed. These are both very unusual faults. Forum user W3DRK does Duet repairs and is based in the US, so you could send him a PM.

paralepsis

Thanks; I've sent a note to Dieter (W3DRK).

Just for my own knowledge, is there a convenient way to map heater 2 (which I understand is an extruder heater and not meant for high current) as the bed heater and then use it to control a DC-DC SSR? Just thinking through my options; apologies if that's stupid for some reason that isn't obvious to me.

EDIT: The M305 X parameter seems to play a role, but that isn't the whole story.

Thanks!

dc42

You can use the M140 H parameter to assign the bed heater to a different heater number.

paralepsis

Thanks!

paralepsis

Dieter confirms bed heater MOSFET was fried; board is on the way back home. Thanks Dieter :).

dc42

@paralepsis:

Dieter confirms bed heater MOSFET was fried; board is on the way back home. Thanks Dieter :).

That's the first time I have heard of that happening. Maybe it was just a case of a bad mosfet, all the same I suggest you check your bed heater wiring carefully for possible shorts.

paralepsis

Printer back up and running, switched over to an Auber SRDD80-5F for managing bed power. All seems well. No obvious problems with the wiring.