From 37d7742468e71272dfd9acfa8bac79be8eca0460 Mon Sep 17 00:00:00 2001 From: Adrian Keet Date: Wed, 2 Sep 2020 06:32:30 -0700 Subject: [PATCH] spi_temperature: fix MAX31865 temperature conversion (#3274) Signed-off-by: Adrian Keet --- docs/Config_Changes.md | 4 ++++ klippy/extras/spi_temperature.py | 2 +- 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/docs/Config_Changes.md b/docs/Config_Changes.md index 13257326..3c14307e 100644 --- a/docs/Config_Changes.md +++ b/docs/Config_Changes.md @@ -6,6 +6,10 @@ All dates in this document are approximate. # Changes +20200902: The RTD resistance-to-temperature calculation for MAX31865 +converters has been corrected to not read low. If you are using such a +device, you should recalibrate your print temperature and PID settings. + 20200816: The gcode macro `printer.gcode` object has been renamed to `printer.gcode_move`. Several undocumented variables in `printer.toolhead` and `printer.gcode` have been removed. See diff --git a/klippy/extras/spi_temperature.py b/klippy/extras/spi_temperature.py index d6f0a2ba..c7ae77a8 100644 --- a/klippy/extras/spi_temperature.py +++ b/klippy/extras/spi_temperature.py @@ -268,7 +268,7 @@ MAX31865_FAULT_RTDINLOW = 0x08 MAX31865_FAULT_OVUV = 0x04 VAL_A = 0.00390830 -VAL_B = 0.0000005775 +VAL_B = -0.0000005775 VAL_C = -0.00000000000418301 VAL_ADC_MAX = 32768.0 # 2^15