RAMPS 1.4: Simulated Heater

Epoxying a 100 kΩ thermistor to a 909 Ω resistor (because I have a bunch of them) serves as a simple heater tester:

Simulated heater - thermistor bonding

Simulated heater – thermistor bonding

It dissipates 450 mW, raising the temperature enough to let the PWM control kick in, but not enough to get scary hot.

Some heatstink tubing prevents reduces the likelihood of horrible accidents involving the 20 V motor / heater power supply:

RAMPS 1.4 - Simulated heaters

RAMPS 1.4 – Simulated heaters

Keeping it under 50 °C seems like a Good Idea:

RAMPS 1.4 - Simulated heater - LCD

RAMPS 1.4 – Simulated heater – LCD

Not that I have a need to heat anything, but the MOSFETs work!



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  1. #1 by Vedran on 2017-11-02 - 14:02

    What version of Marlin is that? It looks very old

    • #2 by Ed on 2017-11-02 - 14:47

      Believe it or not, it’s 1.1.5, one epsilon behind the current head!

      • #3 by Vedran on 2017-11-03 - 09:40

        Almost not :) I did two 1.1.5s a few weeks ago and they look completely different :) Who knows what config options I flipped late in the night and blissfully forgot by the morning :)

        • #4 by Ed on 2017-11-03 - 12:15

          I’m uncomfortable with the pace of Marlin updates, particularly given the wide variety of hardware it must handle; two successive git pull operations may produce firmware with entirely different foibles.