klipper/klippy/extras/spi_temperature.py

357 lines
13 KiB
Python

# Support for common SPI based thermocouple and RTD temperature sensors
#
# 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.
import math, logging
from . import bus
######################################################################
# SensorBase
######################################################################
REPORT_TIME = 0.300
MAX_INVALID_COUNT = 3
class SensorBase:
def __init__(self, config, chip_type, config_cmd=None, spi_mode=1):
self.printer = config.get_printer()
self.chip_type = chip_type
self._callback = None
self.min_sample_value = self.max_sample_value = 0
self._report_clock = 0
self.spi = bus.MCU_SPI_from_config(
config, spi_mode, pin_option="sensor_pin", default_speed=4000000)
if config_cmd is not None:
self.spi.spi_send(config_cmd)
self.mcu = mcu = self.spi.get_mcu()
# Reader chip configuration
self.oid = oid = mcu.create_oid()
mcu.register_response(self._handle_spi_response,
"thermocouple_result", oid)
mcu.register_config_callback(self._build_config)
def setup_minmax(self, min_temp, max_temp):
adc_range = [self.calc_adc(min_temp), self.calc_adc(max_temp)]
self.min_sample_value = min(adc_range)
self.max_sample_value = max(adc_range)
def setup_callback(self, cb):
self._callback = cb
def get_report_time_delta(self):
return REPORT_TIME
def _build_config(self):
self.mcu.add_config_cmd(
"config_thermocouple oid=%u spi_oid=%u thermocouple_type=%s" % (
self.oid, self.spi.get_oid(), self.chip_type))
clock = self.mcu.get_query_slot(self.oid)
self._report_clock = self.mcu.seconds_to_clock(REPORT_TIME)
self.mcu.add_config_cmd(
"query_thermocouple oid=%u clock=%u rest_ticks=%u"
" min_value=%u max_value=%u max_invalid_count=%u" % (
self.oid, clock, self._report_clock,
self.min_sample_value, self.max_sample_value,
MAX_INVALID_COUNT), is_init=True)
def _handle_spi_response(self, params):
if params['fault']:
self.handle_fault(params['value'], params['fault'])
return
temp = self.calc_temp(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)
self._callback(last_read_time, temp)
def report_fault(self, msg):
logging.warning(msg)
######################################################################
# MAX31856 thermocouple
######################################################################
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
MAX31856_SCALE = 5
MAX31856_MULT = 0.0078125
class MAX31856(SensorBase):
def __init__(self, config):
SensorBase.__init__(self, config, "MAX31856",
self.build_spi_init(config))
def handle_fault(self, adc, fault):
if fault & MAX31856_FAULT_CJRANGE:
self.report_fault("Max31856: Cold Junction Range Fault")
if fault & MAX31856_FAULT_TCRANGE:
self.report_fault("Max31856: Thermocouple Range Fault")
if fault & MAX31856_FAULT_CJHIGH:
self.report_fault("Max31856: Cold Junction High Fault")
if fault & MAX31856_FAULT_CJLOW:
self.report_fault("Max31856: Cold Junction Low Fault")
if fault & MAX31856_FAULT_TCHIGH:
self.report_fault("Max31856: Thermocouple High Fault")
if fault & MAX31856_FAULT_TCLOW:
self.report_fault("Max31856: Thermocouple Low Fault")
if fault & MAX31856_FAULT_OVUV:
self.report_fault("Max31856: Over/Under Voltage Fault")
if fault & MAX31856_FAULT_OPEN:
self.report_fault("Max31856: Thermocouple Open Fault")
def calc_temp(self, adc):
adc = adc >> MAX31856_SCALE
# Fix sign bit:
if adc & 0x40000:
adc = ((adc & 0x3FFFF) + 1) * -1
temp = MAX31856_MULT * adc
return temp
def calc_adc(self, temp):
adc = int( ( temp / MAX31856_MULT ) + 0.5 ) # convert to ADC value
adc = max(0, min(0x3FFFF, adc)) << MAX31856_SCALE
return adc
def build_spi_init(self, config):
cmds = []
value = MAX31856_CR0_AUTOCONVERT
if config.getboolean('tc_use_50Hz_filter', False):
value |= MAX31856_CR0_FILT50HZ
cmds.append(0x80 + MAX31856_CR0_REG)
cmds.append(value)
types = {
"B" : 0b0000,
"E" : 0b0001,
"J" : 0b0010,
"K" : 0b0011,
"N" : 0b0100,
"R" : 0b0101,
"S" : 0b0110,
"T" : 0b0111,
}
value = config.getchoice('tc_type', types, default="K")
averages = {
1 : MAX31856_CR1_AVGSEL1,
2 : MAX31856_CR1_AVGSEL2,
4 : MAX31856_CR1_AVGSEL4,
8 : MAX31856_CR1_AVGSEL8,
16 : MAX31856_CR1_AVGSEL16
}
value |= config.getchoice('tc_averaging_count', averages, 1)
cmds.append(value)
value = (MAX31856_MASK_VOLTAGE_UNDER_OVER_FAULT |
MAX31856_MASK_THERMOCOUPLE_OPEN_FAULT)
cmds.append(value)
return cmds
######################################################################
# MAX31855 thermocouple
######################################################################
MAX31855_SCALE = 18
MAX31855_MULT = 0.25
class MAX31855(SensorBase):
def __init__(self, config):
SensorBase.__init__(self, config, "MAX31855", spi_mode=0)
def handle_fault(self, adc, fault):
if fault & 0x1:
self.report_fault("MAX31855 : Open Circuit")
if fault & 0x2:
self.report_fault("MAX31855 : Short to GND")
if fault & 0x4:
self.report_fault("MAX31855 : Short to Vcc")
def calc_temp(self, adc):
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 = max(0, min(0x1FFF, adc)) << MAX31855_SCALE
return adc
######################################################################
# MAX6675 thermocouple
######################################################################
MAX6675_SCALE = 3
MAX6675_MULT = 0.25
class MAX6675(SensorBase):
def __init__(self, config):
SensorBase.__init__(self, config, "MAX6675", spi_mode=0)
def handle_fault(self, adc, fault):
if fault & 0x02:
self.report_fault("Max6675 : Device ID error")
if fault & 0x04:
self.report_fault("Max6675 : Thermocouple Open Fault")
def calc_temp(self, adc):
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 = max(0, min(0x1FFF, adc)) << MAX6675_SCALE
return adc
######################################################################
# 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
MAX31865_ADC_MAX = 1<<15
# Callendar-Van Dusen constants for platinum resistance thermometers (RTD)
CVD_A = 3.9083e-3
CVD_B = -5.775e-7
class MAX31865(SensorBase):
def __init__(self, config):
rtd_nominal_r = config.getfloat('rtd_nominal_r', 100., above=0.)
rtd_reference_r = config.getfloat('rtd_reference_r', 430., above=0.)
adc_to_resist = rtd_reference_r / float(MAX31865_ADC_MAX)
self.adc_to_resist_div_nominal = adc_to_resist / rtd_nominal_r
self.config_reg = self.build_spi_init(config)
SensorBase.__init__(self, config, "MAX31865", self.config_reg)
def handle_fault(self, adc, fault):
if fault & 0x80:
self.report_fault("Max31865 RTD input is disconnected")
if fault & 0x40:
self.report_fault("Max31865 RTD input is shorted")
if fault & 0x20:
self.report_fault(
"Max31865 VREF- is greater than 0.85 * VBIAS, FORCE- open")
if fault & 0x10:
self.report_fault(
"Max31865 VREF- is less than 0.85 * VBIAS, FORCE- open")
if fault & 0x08:
self.report_fault(
"Max31865 VRTD- is less than 0.85 * VBIAS, FORCE- open")
if fault & 0x04:
self.report_fault("Max31865 Overvoltage or undervoltage fault")
if not fault & 0xfc:
self.report_fault("Max31865 Unspecified error")
# Attempt to clear the fault
self.spi.spi_send(self.config_reg)
def calc_temp(self, adc):
adc = adc >> 1 # remove fault bit
R_div_nominal = adc * self.adc_to_resist_div_nominal
# Resistance (relative to rtd_nominal_r) is calculated using:
# R_div_nominal = 1. + CVD_A * temp + CVD_B * temp**2
# Solve for temp using quadratic equation:
# temp = (-b +- sqrt(b**2 - 4ac)) / 2a
discriminant = math.sqrt(CVD_A**2 - 4. * CVD_B * (1. - R_div_nominal))
temp = (-CVD_A + discriminant) / (2. * CVD_B)
return temp
def calc_adc(self, temp):
# Calculate relative resistance via Callendar-Van Dusen formula:
# resistance = rtd_nominal_r * (1 + CVD_A * temp + CVD_B * temp**2)
temp = min(temp, 1768.3) # Melting point of platinum
R_div_nominal = 1. + CVD_A * temp + CVD_B * temp * temp
adc = int(R_div_nominal / self.adc_to_resist_div_nominal + 0.5)
adc = max(0, min(MAX31865_ADC_MAX - 1, adc))
adc = adc << 1 # Add fault bit
return adc
def build_spi_init(self, config):
value = (MAX31865_CONFIG_BIAS |
MAX31865_CONFIG_MODEAUTO |
MAX31865_CONFIG_FAULTCLEAR)
if config.getboolean('rtd_use_50Hz_filter', False):
value |= MAX31865_CONFIG_FILT50HZ
if config.getint('rtd_num_of_wires', 2) == 3:
value |= MAX31865_CONFIG_3WIRE
cmd = 0x80 + MAX31865_CONFIG_REG
return [cmd, value]
######################################################################
# Sensor registration
######################################################################
Sensors = {
"MAX6675": MAX6675,
"MAX31855": MAX31855,
"MAX31856": MAX31856,
"MAX31865": MAX31865,
}
def load_config(config):
# Register sensors
pheaters = config.get_printer().load_object(config, "heaters")
for name, klass in Sensors.items():
pheaters.add_sensor_factory(name, klass)