Need some help on MOSFET for Heat Bed/ Config file

Need some help on MOSFET for Heat Bed/ Config file

So I had it setup with a SSR but after 2 years it burt out, I think the 2.5 Big mosfet on the card also went out, shows 12 volts on it all the time.
(24 Volts Heat Bed only)

So rechecking the docs I see there is now a way to run in SSR mode

So I got this Wangdd22 3D Printer Parts Heating Controller MKS MOSFET for Heat Bed/Extruder MOS Module Exceed 30A Support Big Current
from Amazon

To replace the SSR If I read right it’s better then a SSR??

I set it up on pin 2.5 and the ground next to it
(had it on 2.4 but that is the cooling fan)

But having a hard time understanding the code in the config file …

Here is what I have (I think all wrong) :slight_smile:

the only way I can get it to work was to set “temperature_control.bed.heater_pin 2.5”

does not seem right…


+ show block
# Delta Geometry
# ---------------------------------------------------------------------
arm_solution                    linear_delta
arm_radius                    133.0899
arm_length                    300.0000



default_feed_rate 15000
default_seek_rate 15000
mm_per_arc_segment 0.25
mm_per_line_segment 5
delta_segments_per_second 200

Arm solution configuration : Delta robot. Translates mm positions into stepper positions


alpha_steps_per_mm 160
beta_steps_per_mm 160
gamma_steps_per_mm 160

Planner module configuration : Look-ahead and acceleration configuration


acceleration 1000
acceleration_ticks_per_second 1000
planner_queue_size 32
junction_deviation 0.01



endstops_enable true
delta_homing true
alpha_min_endstop nc
alpha_max_endstop 1.25^
alpha_homing_direction home_to_max
alpha_min 0
alpha_max 0
alpha_max_travel 670
beta_min_endstop nc
beta_max_endstop 1.27^
beta_homing_direction home_to_max
beta_min 0
beta_max 0
beta_max_travel 670
gamma_min_endstop nc
gamma_max_endstop 1.29^
gamma_homing_direction home_to_max
gamma_min 0
gamma_max 341.900
gamma_max_travel 670



alpha_fast_homing_rate_mm_s 100
beta_fast_homing_rate_mm_s 100
gamma_fast_homing_rate_mm_s 100
alpha_slow_homing_rate_mm_s 10
beta_slow_homing_rate_mm_s 10
gamma_slow_homing_rate_mm_s 10
alpha_homing_retract_mm 0
beta_homing_retract_mm 0
gamma_homing_retract_mm 0



alpha_trim -0.454
beta_trim -0.892
gamma_trim -0.806

Stepper module configuration


microseconds_per_step_pulse 1
minimum_steps_per_minute 1200
base_stepping_frequency 100000

Stepper module pins


currentcontrol_module_enable true
alpha_step_pin 2.0
alpha_dir_pin 0.5
alpha_en_pin 0.4
alpha_current 1.7
alpha_max_rate 30000.0
x_axis_max_speed 30000.0
beta_step_pin 2.1
beta_dir_pin 0.11
beta_en_pin 0.10
beta_current 1.7
beta_max_rate 30000.0
y_axis_max_speed 30000.0
gamma_step_pin 2.2
gamma_dir_pin 0.20
gamma_en_pin 0.19
gamma_current 1.7
gamma_max_rate 30000.0
z_axis_max_speed 30000.0

Extruder module configuration


extruder.hotend.enable true
extruder.hotend.steps_per_mm 398.0
extruder.hotend.default_feed_rate 600
extruder.hotend.acceleration 500
extruder.hotend.max_speed 50
extruder.hotend.step_pin 2.3
extruder.hotend.dir_pin 0.22!
extruder.hotend.en_pin 0.21
delta_current 1

Hotend temperature control configuration


temperature_control.hotend.enable true
temperature_control.hotend.thermistor_pin 0.23
temperature_control.hotend.heater_pin 2.7
temperature_control.hotend.thermistor EPCOS100K
#temperature_control.hotend.beta 3590
temperature_control.hotend.set_m_code 104
temperature_control.hotend.set_and_wait_m_code 109
temperature_control.hotend.designator T
temperature_control.hotend.p_factor 27.0
temperature_control.hotend.i_factor 1.5513
temperature_control.hotend.d_factor 120

Heated bed temperature control configuration


switch.temperature_control.bed.enable true #
switch.temperature_control.bed.input_on_command M42 #
switch.temperature_control.bed.input_off_command M43 #
switch.temperature_control.bed.output_pin 2.5 # GPIO pin we connected to “+” on the SSR
switch.temperature_control.bed.output_type digital # just an on or off pin
temperature_control.swimming_pool_heating.heater_pin 2.5
temperature_control.swimming_pool_heating.pwm_frequency 20
temperature_control.bed.enable true
temperature_control.bed.thermistor_pin 0.24
temperature_control.bed.heater_pin 2.5
temperature_control.bed.beta 3974
temperature_control.bed.thermistor Semitec
temperature_control.bed.set_m_code 140
temperature_control.bed.set_and_wait_m_code 190
temperature_control.bed.designator B

temperature_control.bed.bang_bang true

temperature_control.bed.hysteresis 1.0

temperature_control.bed.p_factor 29.6
temperature_control.bed.i_factor .369
temperature_control.bed.d_factor 592

Switch module for fan control

--------------------------------------------------------------------- true M106 M107 2.4 pwm 80

temperatureswitch.hotend.enable true

temperatureswitch.hotend.switch fan2

temperatureswitch.hotend.designator T

temperatureswitch.hotend.threshold_temp 35.0

temperatureswitch.hotend.heatup_poll 15

temperatureswitch.hotend.cooldown_poll 60

switch.fan2.enable true

switch.fan2.input_on_command M42

switch.fan2.input_off_command M43

switch.fan2.output_pin 2.4

LCD Panel


panel.enable true
panel.lcd reprap_discount_glcd
panel.spi_channel 0
panel.spi_cs_pin 0.16
panel.encoder_a_pin 3.25!^
panel.encoder_b_pin 3.26!^
panel.click_button_pin 1.30!^
panel.buzz_pin 1.31
panel.back_button_pin 2.11!^
panel.encoder_resolution 4
panel.menu_offset 0
panel.alpha_jog_feedrate 6000
panel.beta_jog_feedrate 6000
panel.gamma_jog_feedrate 200
panel.hotend_temperature 225
panel.bed_temperature 80
panel.external_sd false

Misc System configuration


pause_button_enable false
return_error_on_unhandled_gcode false
leds_disable false
play_led_disable false
kill_button_enable true
kill_button_pin 2.12
dfu_enable false
msd_disable false

Serial communications configuration


uart0.baud_rate 115200
second_usb_serial_enable false

network settings


network.enable false

network.webserver.enable true

network.telnet.enable true




If you have a Z probe, you can select a calibration strategy here

To calculate probe_offset_x/y/z:

- Heat up the hot end with filament loaded - and the print surface, if you have bed heat (this is important!)

- Jog the hot end down to the print surface, leaving a little dot of plastic

- Deploy the probe, jog it until the probe tip touches the dot

- Jog the probe up a little, remove the dot, jog it down until it triggers, and record the exact values in offset_x/y/z

PLEASE NOTE: probe_offset_x and probe_offset_y MUST be 0 if you want to use depth (Z) correction!


leveling-strategy.comprehensive-delta.enable true 135 # the probe radius
leveling-strategy.three-point-leveling.tolerance 0.01
comprehensive-delta.probe_smoothing 4 # if your probe has repeatability issues, this will probe multiple times & take the average (default 1)
comprehensive-delta.probe_priming 3 # if your probe keeps “creeping down”, this will run it the specified number of times to get it to settle
comprehensive-delta.probe_acceleration 100 # acceleration will be temporarily set to this during probing; original is restored later; 100 is a good value
comprehensive-delta.probe_offset_x 0 # distance between the probe and the nozzle
comprehensive-delta.probe_offset_y 0 #
comprehensive-delta.probe_offset_z 0 #

Optional Z probe, see


probe endstop
probe_pin 1.28 # optional pin for probe
zprobe.enable true # set to true to enable a zprobe
zprobe.probe_pin 1.28!^ # pin probe is attached to if NC remove the !, default 1.29!^
zprobe.slow_feedrate 3 # mm/sec probe feed rate
zprobe.fast_feedrate 50 # move feedrate
zprobe.debounce_count 0 # set if noisy
zprobe.probe_radius 110 # how far out from bed center to probe
zprobe.probe_height 20 # how high the probe has to be moved above trigger elevation so that it won’t drag
zprobe.decelerate_on_trigger true # beneficial, unless your probe has no runout after it hits the trigger - in which case, set this to false
zprobe.decelerate_runout 0 # how many millimeters your probe can move past the trigger point; we’ll abort any decel > this long


Its the “Switch” part I’m having problems with

Imported from wikidot

Seems it messed my code all up… Can not seems to add the config file here… How does one do that?

Post it on and give us the link, is the simplest method.

Note : to get to the forum you should have had to go through this page : which explains the rules of this forum, but also how to post config either using tags, or pastebin. Read it.

The link :

Ok a few comments based on your config file and your email.

  1. You seem to be confused about temperaturecontrol and switch, they are very different modules, see the documentation for each
  2. You are rewriting your config file from scratch, that is a horrible idea. Please use the example config file and modify it *as little as you strictly need*
  3. Yes there is a list of all config options, see the home page
  4. All your questions so far have their answer in the documentation, I recommend you read the documentation