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Upgraded to ReArm, heated bed issue

Posted by eboaen 
Upgraded to ReArm, heated bed issue
February 02, 2017 11:07PM
Currently have a Reprapguru Prusa i3 mk2.

I just upgraded the main board to the new Re-Arm smoothie board.
I had previously done a rewire of the heated bed to put a 12v relay in as I melted the mosfet connector on my first RAMPs board, and I've found the wiring provided with the old board to be extremely subbar.
Now when I start the heater for my bed, I can hear the relay clicking over and over and over. I didn't like the sound so turned off the heater.
Any ideas if this can be solved firmware config-wise? Attached my current smoothie firmware config.
open | download - config.txt (22.9 KB)
Re: Upgraded to ReArm, heated bed issue
February 02, 2017 11:23PM
And solved my own problem!

Read up a bit and found this:

temperature_control.bed.bang_bang true # set to true to use bang bang control rather than PID
temperature_control.bed.hysteresis 2.0 # set to the temperature in degrees C to use as hysteresis when
Re: Upgraded to ReArm, heated bed issue
February 03, 2017 02:24AM
Why not replace the relay with a seperate control Mosfet instead.

This will be silent and can be driven from the original bed output. This would allow you to go back to PID control of bed temperature, which gives much better results. Mechanical relays also have a finite life depending on how frequently they switch. There are a number of suitable boards available on Amazon or Ebay, I run one myself.
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