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spi_temperature: Break up thermocouple code into individual classes 

Break the Thermocouple() class into MAX31856(), MAX31855(), and
MAX6675() classes.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor 2018-07-24 14:45:00 -04:00
parent 7510efe827
commit f20dd0c9be
1 changed files with 115 additions and 74 deletions
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127
klippy/extras/spi_temperature.py
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@ -1,6 +1,7 @@
# Support for common SPI based thermocouple and RTD temperature sensors # Support for common SPI based thermocouple and RTD temperature sensors
# #
# Copyright (C) 2018 Petri Honkala <cruwaller@gmail.com> # Copyright (C) 2018 Petri Honkala <cruwaller@gmail.com>
# Copyright (C) 2018 Kevin O'Connor <kevin@koconnor.net>
# #
# This file may be distributed under the terms of the GNU GPLv3 license. # This file may be distributed under the terms of the GNU GPLv3 license.
import math import math
@ -80,7 +81,7 @@ class SensorBase:
###################################################################### ######################################################################
# Thermocouples # MAX31856 thermocouple
###################################################################### ######################################################################
MAX31856_CR0_REG = 0x00 MAX31856_CR0_REG = 0x00
@ -132,9 +133,12 @@ MAX31856_FAULT_TCLOW = 0x04 # Thermocouple Low
MAX31856_FAULT_OVUV = 0x02 # Under Over Voltage MAX31856_FAULT_OVUV = 0x02 # Under Over Voltage
MAX31856_FAULT_OPEN = 0x01 MAX31856_FAULT_OPEN = 0x01
class Thermocouple(SensorBase): MAX31856_SCALE = 5
MAX31856_MULT = 0.0078125
class MAX31856(SensorBase):
def __init__(self, config): def __init__(self, config):
self.chip_type = chip_type = config.get('sensor_type') self.chip_type = "MAX31856"
types = { types = {
"B" : 0b0000, "B" : 0b0000,
"E" : 0b0001, "E" : 0b0001,
@ -155,31 +159,8 @@ class Thermocouple(SensorBase):
"16" : MAX31856_CR1_AVGSEL16 "16" : MAX31856_CR1_AVGSEL16
} }
self.average_count = config.getchoice('tc_averaging_count', averages, "1") self.average_count = config.getchoice('tc_averaging_count', averages, "1")
if chip_type == "MAX31856":
self.val_a = 0.0078125
self.scale = 5
elif chip_type == "MAX6675":
self.val_a = 0.25
self.scale = 3
else:
self.val_a = 0.25
self.scale = 18
SensorBase.__init__(self, config) SensorBase.__init__(self, config)
def _check_faults_simple(self, val):
if self.chip_type == "MAX6675":
if val & 0x02:
raise self.error("Max6675 : Device ID error")
if val & 0x04:
raise self.error("Max6675 : Thermocouple Open Fault")
elif not self.chip_type == "MAX31856":
if val & 0x1:
raise self.error("MAX31855 : Open Circuit")
if val & 0x2:
raise self.error("MAX31855 : Short to GND")
if val & 0x4:
raise self.error("MAX31855 : Short to Vcc")
def check_faults(self, fault): def check_faults(self, fault):
if self.chip_type == "MAX31856":
if fault & MAX31856_FAULT_CJRANGE: if fault & MAX31856_FAULT_CJRANGE:
raise self.error("Max31856: Cold Junction Range Fault") raise self.error("Max31856: Cold Junction Range Fault")
if fault & MAX31856_FAULT_TCRANGE: if fault & MAX31856_FAULT_TCRANGE:
@ -197,24 +178,18 @@ class Thermocouple(SensorBase):
if fault & MAX31856_FAULT_OPEN: if fault & MAX31856_FAULT_OPEN:
raise self.error("Max31856: Thermocouple Open Fault") raise self.error("Max31856: Thermocouple Open Fault")
def calc_temp(self, adc): def calc_temp(self, adc):
self._check_faults_simple(adc) adc = adc >> MAX31856_SCALE
adc = adc >> self.scale
# Fix sign bit: # Fix sign bit:
if self.chip_type == "MAX31856":
if adc & 0x40000: if adc & 0x40000:
adc = ((adc & 0x3FFFF) + 1) * -1 adc = ((adc & 0x3FFFF) + 1) * -1
else: temp = MAX31856_MULT * adc
if adc & 0x2000:
adc = ((adc & 0x1FFF) + 1) * -1
temp = self.val_a * adc
return temp return temp
def calc_adc(self, temp): def calc_adc(self, temp):
adc = int ( ( temp / self.val_a ) + 0.5 ) # convert to ADC value adc = int( ( temp / MAX31856_MULT ) + 0.5 ) # convert to ADC value
adc = adc << self.scale adc = adc << MAX31856_SCALE
return adc return adc
def get_configs(self): def get_configs(self):
cmds = [] cmds = []
if self.chip_type == "MAX31856":
value = MAX31856_CR0_AUTOCONVERT value = MAX31856_CR0_AUTOCONVERT
if self.use_50Hz_filter: if self.use_50Hz_filter:
value |= MAX31856_CR0_FILT50HZ value |= MAX31856_CR0_FILT50HZ
@ -233,6 +208,72 @@ class Thermocouple(SensorBase):
return cmds return cmds
######################################################################
# MAX31855 thermocouple
######################################################################
MAX31855_SCALE = 18
MAX31855_MULT = 0.25
class MAX31855(SensorBase):
def __init__(self, config):
self.chip_type = "MAX31855"
SensorBase.__init__(self, config)
def check_faults(self, fault):
pass
def calc_temp(self, adc):
if adc & 0x1:
raise self.error("MAX31855 : Open Circuit")
if adc & 0x2:
raise self.error("MAX31855 : Short to GND")
if adc & 0x4:
raise self.error("MAX31855 : Short to Vcc")
adc = adc >> MAX31855_SCALE
# Fix sign bit:
if adc & 0x2000:
adc = ((adc & 0x1FFF) + 1) * -1
temp = MAX31855_MULT * adc
return temp
def calc_adc(self, temp):
adc = int( ( temp / MAX31855_MULT ) + 0.5 ) # convert to ADC value
adc = adc << MAX31855_SCALE
return adc
def get_configs(self):
return []
######################################################################
# MAX6675 thermocouple
######################################################################
MAX6675_SCALE = 3
MAX6675_MULT = 0.25
class MAX6675(SensorBase):
def __init__(self, config):
self.chip_type = "MAX6675"
SensorBase.__init__(self, config)
def check_faults(self, fault):
pass
def calc_temp(self, adc):
if adc & 0x02:
raise self.error("Max6675 : Device ID error")
if adc & 0x04:
raise self.error("Max6675 : Thermocouple Open Fault")
adc = adc >> MAX6675_SCALE
# Fix sign bit:
if adc & 0x2000:
adc = ((adc & 0x1FFF) + 1) * -1
temp = MAX6675_MULT * adc
return temp
def calc_adc(self, temp):
adc = int( ( temp / MAX6675_MULT ) + 0.5 ) # convert to ADC value
adc = adc << MAX6675_SCALE
return adc
def get_configs(self):
return []
###################################################################### ######################################################################
# MAX31865 (RTD sensor) # MAX31865 (RTD sensor)
###################################################################### ######################################################################
@ -265,9 +306,9 @@ VAL_B = 0.0000005775
VAL_C = -0.00000000000418301 VAL_C = -0.00000000000418301
VAL_ADC_MAX = 32768.0 # 2^15 VAL_ADC_MAX = 32768.0 # 2^15
class RTD(SensorBase): class MAX31865(SensorBase):
def __init__(self, config): def __init__(self, config):
self.chip_type = config.get('sensor_type') self.chip_type = "MAX31865"
self.rtd_nominal_r = config.getint('rtd_nominal_r', 100) self.rtd_nominal_r = config.getint('rtd_nominal_r', 100)
self.reference_r = config.getfloat('rtd_reference_r', 430., above=0.) self.reference_r = config.getfloat('rtd_reference_r', 430., above=0.)
self.num_wires = config.getint('rtd_num_of_wires', 2) self.num_wires = config.getint('rtd_num_of_wires', 2)
@ -303,7 +344,7 @@ class RTD(SensorBase):
R_rtd = -1 * ( R_rtd - ( self.rtd_nominal_r * self.rtd_nominal_r * VAL_A * VAL_A ) ) R_rtd = -1 * ( R_rtd - ( self.rtd_nominal_r * self.rtd_nominal_r * VAL_A * VAL_A ) )
R_rtd = R_rtd / ( 4 * self.rtd_nominal_r * VAL_B ) R_rtd = R_rtd / ( 4 * self.rtd_nominal_r * VAL_B )
R_rtd = ( -1 * R_rtd ) + self.rtd_nominal_r R_rtd = ( -1 * R_rtd ) + self.rtd_nominal_r
adc = int ( ( ( R_rtd * VAL_ADC_MAX ) / self.reference_r) + 0.5 ) adc = int( ( ( R_rtd * VAL_ADC_MAX ) / self.reference_r) + 0.5 )
adc = adc << 1 # Add fault bit adc = adc << 1 # Add fault bit
return adc return adc
def get_configs(self): def get_configs(self):
@ -323,10 +364,10 @@ class RTD(SensorBase):
###################################################################### ######################################################################
Sensors = { Sensors = {
"MAX6675": Thermocouple, "MAX6675": MAX6675,
"MAX31855": Thermocouple, "MAX31855": MAX31855,
"MAX31856": Thermocouple, "MAX31856": MAX31856,
"MAX31865": RTD, "MAX31865": MAX31865,
} }
def load_config(config): def load_config(config):