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adc_temperature: Calculate "PT100 INA826" values from formula 

Calculate the "PT100 INA826" values instead of using a voltage table.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor 2020-08-22 17:01:35 -04:00
parent d3e41b55b7
commit 4a6360f2af
1 changed files with 7 additions and 13 deletions
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20
klippy/extras/adc_temperature.py
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@ -261,19 +261,6 @@ AD8497 = [
(1360, 6.671), (1380, 6.754)
]
PT100 = [
(0, 0.00), (1, 1.11), (10, 1.15), (20, 1.20), (30, 1.24), (40, 1.28),
(50, 1.32), (60, 1.36), (70, 1.40), (80, 1.44), (90, 1.48), (100, 1.52),
(110, 1.56), (120, 1.61), (130, 1.65), (140, 1.68), (150, 1.72),
(160, 1.76), (170, 1.80), (180, 1.84), (190, 1.88), (200, 1.92),
(210, 1.96), (220, 2.00), (230, 2.04), (240, 2.07), (250, 2.11),
(260, 2.15), (270, 2.18), (280, 2.22), (290, 2.26), (300, 2.29),
(310, 2.33), (320, 2.37), (330, 2.41), (340, 2.44), (350, 2.48),
(360, 2.51), (370, 2.55), (380, 2.58), (390, 2.62), (400, 2.66),
(500, 3.00), (600, 3.33), (700, 3.63), (800, 3.93), (900, 4.21),
(1000, 4.48), (1100, 4.73)
]
def calc_pt1000():
# Calc PT1000 temperature/resistance pairs using formula
A, B = (3.9083e-3, -5.775e-7)
@ -281,6 +268,13 @@ def calc_pt1000():
PT1000 = calc_pt1000()
def calc_ina826_pt100():
PT100 = [(t, .1 * r) for t, r in PT1000]
# Standard circuit is 4400ohm pullup with 10x gain to 5V
return [(t, 10. * 5. * r / (4400. + r)) for t, r in PT100]
PT100 = calc_ina826_pt100()
def load_config(config):
# Register default sensors
pheaters = config.get_printer().load_object(config, "heaters")