klipper-dgus/klippy/extras/spi_temperature.py

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# Support for common SPI based thermocouple and RTD temperature sensors
#
# Copyright (C) 2018 Petri Honkala <cruwaller@gmail.com>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
import math
######################################################################
# SensorBase
######################################################################
SAMPLE_TIME_DEFAULT = 0.001
SAMPLE_COUNT_DEFAULT = 8
REPORT_TIME_DEFAULT = 0.300
VALID_SPI_SENSORS = {
'MAX6675' : 1, 'MAX31855' : 1,
'MAX31856' : 2,
'MAX31865' : 4
}
class error(Exception):
pass
class SensorBase(object):
error = error
def __init__(self,
config,
is_spi = False,
sample_time = SAMPLE_TIME_DEFAULT,
sample_count = SAMPLE_COUNT_DEFAULT,
report_time = REPORT_TIME_DEFAULT):
self.is_spi = is_spi
self.sample_time = sample_time
self.sample_count = sample_count
self.report_time = report_time
self.min_temp = config.getfloat('min_temp', minval=0., default=0.)
self.max_temp = config.getfloat('max_temp', above=self.min_temp)
self._callback = None
sensor_pin = config.get('sensor_pin')
adc_range = [self.calc_adc(self.min_temp),
self.calc_adc(self.max_temp)]
self.min_sample_value = min(adc_range)
self.max_sample_value = max(adc_range)
self._report_clock = 0
ppins = config.get_printer().lookup_object('pins')
if is_spi:
pin_params = ppins.lookup_pin('digital_out', sensor_pin)
self.mcu = mcu = pin_params['chip']
pin = pin_params['pin']
# SPI bus configuration
spi_oid = mcu.create_oid()
spi_mode = config.getint('spi_mode', minval=0, maxval=3)
spi_speed = config.getint('spi_speed', minval=0)
mcu.add_config_cmd(
"config_spi oid=%u bus=%u pin=%s"
" mode=%u rate=%u shutdown_msg=" % (
spi_oid, 0, pin, spi_mode, spi_speed))
config_cmd = "".join("%02x" % b for b in self.get_configs())
mcu.add_config_cmd("spi_send oid=%u data=%s" % (
spi_oid, config_cmd), is_init=True)
# Reader chip configuration
self.oid = oid = mcu.create_oid()
mcu.add_config_cmd(
"config_thermocouple oid=%u spi_oid=%u chip_type=%u" % (
oid, spi_oid, VALID_SPI_SENSORS[self.chip_type]))
mcu.register_msg(self._handle_spi_response,
"thermocouple_result", oid)
mcu.add_config_object(self)
else:
self.mcu = ppins.setup_pin('adc', sensor_pin)
self.mcu.setup_minmax(
sample_time, sample_count,
minval=min(adc_range), maxval=max(adc_range))
def setup_minmax(self, min_temp, max_temp):
pass
def setup_callback(self, cb):
if self.is_spi:
self._callback = cb
else:
self.mcu.setup_callback(self.report_time, cb)
def get_report_time_delta(self):
return self.report_time
def build_config(self):
clock = self.mcu.get_query_slot(self.oid)
self._report_clock = self.mcu.seconds_to_clock(self.report_time)
self.mcu.add_config_cmd(
"query_thermocouple oid=%u clock=%u rest_ticks=%u"
" min_value=%u max_value=%u" % (
self.oid, clock, self._report_clock,
self.min_sample_value, self.max_sample_value))
def _handle_spi_response(self, params):
last_value = params['value']
next_clock = self.mcu.clock32_to_clock64(params['next_clock'])
last_read_clock = next_clock - self._report_clock
last_read_time = self.mcu.clock_to_print_time(last_read_clock)
temp = self.calc_temp(last_value)
self.check_faults(params['fault'])
if self._callback is not None:
self._callback(last_read_time, temp)
######################################################################
# Thermocouples
######################################################################
MAX31856_CR0_REG = 0x00
MAX31856_CR0_AUTOCONVERT = 0x80
MAX31856_CR0_1SHOT = 0x40
MAX31856_CR0_OCFAULT1 = 0x20
MAX31856_CR0_OCFAULT0 = 0x10
MAX31856_CR0_CJ = 0x08
MAX31856_CR0_FAULT = 0x04
MAX31856_CR0_FAULTCLR = 0x02
MAX31856_CR0_FILT50HZ = 0x01
MAX31856_CR0_FILT60HZ = 0x00
MAX31856_CR1_REG = 0x01
MAX31856_CR1_AVGSEL1 = 0x00
MAX31856_CR1_AVGSEL2 = 0x10
MAX31856_CR1_AVGSEL4 = 0x20
MAX31856_CR1_AVGSEL8 = 0x30
MAX31856_CR1_AVGSEL16 = 0x70
MAX31856_MASK_REG = 0x02
MAX31856_MASK_COLD_JUNCTION_HIGH_FAULT = 0x20
MAX31856_MASK_COLD_JUNCTION_LOW_FAULT = 0x10
MAX31856_MASK_THERMOCOUPLE_HIGH_FAULT = 0x08
MAX31856_MASK_THERMOCOUPLE_LOW_FAULT = 0x04
MAX31856_MASK_VOLTAGE_UNDER_OVER_FAULT = 0x02
MAX31856_MASK_THERMOCOUPLE_OPEN_FAULT = 0x01
MAX31856_CJHF_REG = 0x03
MAX31856_CJLF_REG = 0x04
MAX31856_LTHFTH_REG = 0x05
MAX31856_LTHFTL_REG = 0x06
MAX31856_LTLFTH_REG = 0x07
MAX31856_LTLFTL_REG = 0x08
MAX31856_CJTO_REG = 0x09
MAX31856_CJTH_REG = 0x0A
MAX31856_CJTL_REG = 0x0B
MAX31856_LTCBH_REG = 0x0C
MAX31856_LTCBM_REG = 0x0D
MAX31856_LTCBL_REG = 0x0E
MAX31856_SR_REG = 0x0F
MAX31856_FAULT_CJRANGE = 0x80 # Cold Junction out of range
MAX31856_FAULT_TCRANGE = 0x40 # Thermocouple out of range
MAX31856_FAULT_CJHIGH = 0x20 # Cold Junction High
MAX31856_FAULT_CJLOW = 0x10 # Cold Junction Low
MAX31856_FAULT_TCHIGH = 0x08 # Thermocouple Low
MAX31856_FAULT_TCLOW = 0x04 # Thermocouple Low
MAX31856_FAULT_OVUV = 0x02 # Under Over Voltage
MAX31856_FAULT_OPEN = 0x01
class Thermocouple(SensorBase):
def __init__(self, config):
self.chip_type = chip_type = config.get('sensor_type')
types = {
"B" : 0b0000,
"E" : 0b0001,
"J" : 0b0010,
"K" : 0b0011,
"N" : 0b0100,
"R" : 0b0101,
"S" : 0b0110,
"T" : 0b0111,
}
self.tc_type = config.getchoice('tc_type', types, default="K")
self.use_50Hz_filter = config.getboolean('tc_use_50Hz_filter', False)
averages = {
"1" : MAX31856_CR1_AVGSEL1,
"2" : MAX31856_CR1_AVGSEL2,
"4" : MAX31856_CR1_AVGSEL4,
"8" : MAX31856_CR1_AVGSEL8,
"16" : MAX31856_CR1_AVGSEL16
}
self.average_count = config.getchoice('tc_averaging_count', averages, "1")
if chip_type == "MAX31856":
self.val_a = 0.0078125
self.scale = 5
else:
self.val_a = 0.25
self.scale = 18
SensorBase.__init__(self, config, is_spi = True, sample_count = 1)
def _check_faults_simple(self, val):
if not self.chip_type == "MAX31856":
if val & 0x1:
raise self.error("MAX6675/MAX31855 : Open Circuit")
if val & 0x2:
raise self.error("MAX6675/MAX31855 : Short to GND")
if val & 0x4:
raise self.error("MAX6675/MAX31855 : Short to Vcc")
def check_faults(self, fault):
if self.chip_type == "MAX31856":
if fault & MAX31856_FAULT_CJRANGE:
raise self.error("Max31856: Cold Junction Range Fault")
if fault & MAX31856_FAULT_TCRANGE:
raise self.error("Max31856: Thermocouple Range Fault")
if fault & MAX31856_FAULT_CJHIGH:
raise self.error("Max31856: Cold Junction High Fault")
if fault & MAX31856_FAULT_CJLOW:
raise self.error("Max31856: Cold Junction Low Fault")
if fault & MAX31856_FAULT_TCHIGH:
raise self.error("Max31856: Thermocouple High Fault")
if fault & MAX31856_FAULT_TCLOW:
raise self.error("Max31856: Thermocouple Low Fault")
if fault & MAX31856_FAULT_OVUV:
raise self.error("Max31856: Over/Under Voltage Fault")
if fault & MAX31856_FAULT_OPEN:
raise self.error("Max31856: Thermocouple Open Fault")
def calc_temp(self, adc):
self._check_faults_simple(adc)
adc = adc >> self.scale
# Fix sign bit:
if self.chip_type == "MAX31856":
if adc & 0x40000:
adc = ((adc & 0x3FFFF) + 1) * -1
else:
if adc & 0x2000:
adc = ((adc & 0x1FFF) + 1) * -1
temp = self.val_a * adc
return temp
def calc_adc(self, temp):
adc = int ( ( temp / self.val_a ) + 0.5 ) # convert to ADC value
adc = adc << self.scale
return adc
def get_configs(self):
cmds = []
if self.chip_type == "MAX31856":
value = MAX31856_CR0_AUTOCONVERT
if self.use_50Hz_filter:
value |= MAX31856_CR0_FILT50HZ
cmds.append(0x80 + MAX31856_CR0_REG)
cmds.append(value)
value = self.tc_type
value |= self.average_count
cmds.append(0x80 + MAX31856_CR1_REG)
cmds.append(value)
value = (MAX31856_MASK_VOLTAGE_UNDER_OVER_FAULT |
MAX31856_MASK_THERMOCOUPLE_OPEN_FAULT)
cmds.append(0x80 + MAX31856_MASK_REG)
cmds.append(value)
return cmds
######################################################################
# MAX31865 (RTD sensor)
######################################################################
MAX31865_CONFIG_REG = 0x00
MAX31865_RTDMSB_REG = 0x01
MAX31865_RTDLSB_REG = 0x02
MAX31865_HFAULTMSB_REG = 0x03
MAX31865_HFAULTLSB_REG = 0x04
MAX31865_LFAULTMSB_REG = 0x05
MAX31865_LFAULTLSB_REG = 0x06
MAX31865_FAULTSTAT_REG = 0x07
MAX31865_CONFIG_BIAS = 0x80
MAX31865_CONFIG_MODEAUTO = 0x40
MAX31865_CONFIG_1SHOT = 0x20
MAX31865_CONFIG_3WIRE = 0x10
MAX31865_CONFIG_FAULTCLEAR = 0x02
MAX31865_CONFIG_FILT50HZ = 0x01
MAX31865_FAULT_HIGHTHRESH = 0x80
MAX31865_FAULT_LOWTHRESH = 0x40
MAX31865_FAULT_REFINLOW = 0x20
MAX31865_FAULT_REFINHIGH = 0x10
MAX31865_FAULT_RTDINLOW = 0x08
MAX31865_FAULT_OVUV = 0x04
VAL_A = 0.00390830
VAL_B = 0.0000005775
VAL_C = -0.00000000000418301
VAL_ADC_MAX = 32768.0 # 2^15
class RTD(SensorBase):
def __init__(self, config):
self.chip_type = config.get('sensor_type')
self.rtd_nominal_r = config.getint('rtd_nominal_r', 100)
self.reference_r = config.getfloat('rtd_reference_r', 430., above=0.)
self.num_wires = config.getint('rtd_num_of_wires', 2)
self.use_50Hz_filter = config.getboolean('rtd_use_50Hz_filter', False)
SensorBase.__init__(self, config, is_spi = True, sample_count = 1)
def check_faults(self, fault):
if fault & 0x80:
raise self.error("Max31865 RTD input is disconnected")
if fault & 0x40:
raise self.error("Max31865 RTD input is shorted")
if fault & 0x20:
raise self.error("Max31865 VREF- is greater than 0.85 * VBIAS, FORCE- open")
if fault & 0x10:
raise self.error("Max31865 VREF- is less than 0.85 * VBIAS, FORCE- open")
if fault & 0x08:
raise self.error("Max31865 VRTD- is less than 0.85 * VBIAS, FORCE- open")
if fault & 0x04:
raise self.error("Max31865 Overvoltage or undervoltage fault")
if fault & 0x03:
raise self.error("Max31865 Unspecified error")
def calc_temp(self, adc):
adc = adc >> 1 # remove fault bit
R_rtd = (self.reference_r * adc) / VAL_ADC_MAX
temp = (
(( ( -1 * self.rtd_nominal_r ) * VAL_A ) +
math.sqrt( ( self.rtd_nominal_r * self.rtd_nominal_r * VAL_A * VAL_A ) -
( 4 * self.rtd_nominal_r * VAL_B * ( self.rtd_nominal_r - R_rtd ) )))
/ (2 * self.rtd_nominal_r * VAL_B))
return temp
def calc_adc(self, temp):
R_rtd = temp * ( 2 * self.rtd_nominal_r * VAL_B )
R_rtd = math.pow( ( R_rtd + ( self.rtd_nominal_r * VAL_A ) ), 2)
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 = ( -1 * R_rtd ) + self.rtd_nominal_r
adc = int ( ( ( R_rtd * VAL_ADC_MAX ) / self.reference_r) + 0.5 )
adc = adc << 1 # Add fault bit
return adc
def get_configs(self):
value = (MAX31865_CONFIG_BIAS |
MAX31865_CONFIG_MODEAUTO |
MAX31865_CONFIG_FAULTCLEAR)
if self.use_50Hz_filter:
value |= MAX31865_CONFIG_FILT50HZ
if self.num_wires == 3:
value |= MAX31865_CONFIG_3WIRE
cmd = 0x80 + MAX31865_CONFIG_REG
return [cmd, value]
######################################################################
# Sensor registration
######################################################################
Sensors = {
"MAX6675": Thermocouple,
"MAX31855": Thermocouple,
"MAX31856": Thermocouple,
"MAX31865": RTD,
}
def load_config(config):
# Register sensors
pheater = config.get_printer().lookup_object("heater")
for name, klass in Sensors.items():
pheater.add_sensor(name, klass)