Bed heater: PWM frequence and hysteresis adjustable?
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Hi guys,
I'm using an old Prusa i3 heated bed to regulate temp in a 10l fishtank.
It works OK in bang-bang mode with max. power reduced to 0.6, but that makes the powersupply hum very often at an audible frequence.
I checked the wiki, but couldn't find ways to lower the PWM-freq or increase the hysteresis to +/- 1degree.Plan B would be to add a LiPo battery to the powersupply, hoping to smooth out the sharp PWM transitions. But I hope to find help here with a FW solution.
THX -
You can adjust the PWM frequency with the M950 Q for the pin definition. Not sure about hysteresis, but if you PID tune it, it should be pretty stable, no?
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@o_lampe using bang-bang mode on a bed heater frequently gives rise to Z-banding, so we discourage it. Using hysteresis would make the Z-banding worse.
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@o_lampe said in Bed heater: PWM frequence and hysteresis adjustable?:
regulate temp in a 10l fishtank.
Do the fish get z banding?
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@Phaedrux According to "I read only the headline"-David it's possible
Nevermind, he's a busy man...and my usecase is offtopic at best.With the 12V LiPo battery in parallel, the humming got significantly quieter. But it still hums even with the PSU switched off??
I'll try to set the PWM to a less disturbing freq and everyone's happy.
