354 lines
13 KiB
Python
354 lines
13 KiB
Python
# Support for common SPI based thermocouple and RTD temperature sensors
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#
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# Copyright (C) 2018 Petri Honkala <cruwaller@gmail.com>
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# Copyright (C) 2018 Kevin O'Connor <kevin@koconnor.net>
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#
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# This file may be distributed under the terms of the GNU GPLv3 license.
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import math
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# Sensor types defined in the micro-controller code (thermocouple.c)
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TS_CHIP_MAX31855 = 1 << 0
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TS_CHIP_MAX31856 = 1 << 1
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TS_CHIP_MAX31865 = 1 << 2
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TS_CHIP_MAX6675 = 1 << 3
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######################################################################
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# SensorBase
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######################################################################
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REPORT_TIME = 0.300
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class SensorBase:
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def __init__(self, config, chip_type, config_cmd=None):
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self.printer = config.get_printer()
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self._callback = None
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self.min_sample_value = self.max_sample_value = 0
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self._report_clock = 0
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ppins = config.get_printer().lookup_object('pins')
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pin_params = ppins.lookup_pin(config.get('sensor_pin'))
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self.mcu = mcu = pin_params['chip']
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pin = pin_params['pin']
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# SPI bus configuration
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spi_oid = mcu.create_oid()
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spi_speed = config.getint('spi_speed', 4000000, minval=1)
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mcu.add_config_cmd(
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"config_spi oid=%u bus=0 pin=%s mode=1 rate=%u shutdown_msg=" % (
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spi_oid, pin, spi_speed))
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if config_cmd is not None:
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config_cmd = "".join("%02x" % b for b in config_cmd)
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mcu.add_config_cmd("spi_send oid=%u data=%s" % (
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spi_oid, config_cmd), is_init=True)
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# Reader chip configuration
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self.oid = oid = mcu.create_oid()
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mcu.add_config_cmd(
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"config_thermocouple oid=%u spi_oid=%u chip_type=%u" % (
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oid, spi_oid, chip_type))
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mcu.register_msg(self._handle_spi_response,
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"thermocouple_result", oid)
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mcu.add_config_object(self)
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def setup_minmax(self, min_temp, max_temp):
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adc_range = [self.calc_adc(min_temp), self.calc_adc(max_temp)]
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self.min_sample_value = min(adc_range)
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self.max_sample_value = max(adc_range)
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def setup_callback(self, cb):
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self._callback = cb
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def get_report_time_delta(self):
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return REPORT_TIME
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def build_config(self):
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clock = self.mcu.get_query_slot(self.oid)
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self._report_clock = self.mcu.seconds_to_clock(REPORT_TIME)
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self.mcu.add_config_cmd(
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"query_thermocouple oid=%u clock=%u rest_ticks=%u"
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" min_value=%u max_value=%u" % (
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self.oid, clock, self._report_clock,
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self.min_sample_value, self.max_sample_value), is_init=True)
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def _handle_spi_response(self, params):
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temp = self.calc_temp(params['value'], params['fault'])
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next_clock = self.mcu.clock32_to_clock64(params['next_clock'])
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last_read_clock = next_clock - self._report_clock
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last_read_time = self.mcu.clock_to_print_time(last_read_clock)
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self._callback(last_read_time, temp)
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def fault(self, msg):
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self.printer.invoke_async_shutdown(msg)
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######################################################################
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# MAX31856 thermocouple
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######################################################################
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MAX31856_CR0_REG = 0x00
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MAX31856_CR0_AUTOCONVERT = 0x80
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MAX31856_CR0_1SHOT = 0x40
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MAX31856_CR0_OCFAULT1 = 0x20
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MAX31856_CR0_OCFAULT0 = 0x10
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MAX31856_CR0_CJ = 0x08
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MAX31856_CR0_FAULT = 0x04
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MAX31856_CR0_FAULTCLR = 0x02
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MAX31856_CR0_FILT50HZ = 0x01
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MAX31856_CR0_FILT60HZ = 0x00
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MAX31856_CR1_REG = 0x01
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MAX31856_CR1_AVGSEL1 = 0x00
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MAX31856_CR1_AVGSEL2 = 0x10
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MAX31856_CR1_AVGSEL4 = 0x20
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MAX31856_CR1_AVGSEL8 = 0x30
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MAX31856_CR1_AVGSEL16 = 0x70
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MAX31856_MASK_REG = 0x02
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MAX31856_MASK_COLD_JUNCTION_HIGH_FAULT = 0x20
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MAX31856_MASK_COLD_JUNCTION_LOW_FAULT = 0x10
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MAX31856_MASK_THERMOCOUPLE_HIGH_FAULT = 0x08
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MAX31856_MASK_THERMOCOUPLE_LOW_FAULT = 0x04
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MAX31856_MASK_VOLTAGE_UNDER_OVER_FAULT = 0x02
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MAX31856_MASK_THERMOCOUPLE_OPEN_FAULT = 0x01
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MAX31856_CJHF_REG = 0x03
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MAX31856_CJLF_REG = 0x04
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MAX31856_LTHFTH_REG = 0x05
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MAX31856_LTHFTL_REG = 0x06
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MAX31856_LTLFTH_REG = 0x07
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MAX31856_LTLFTL_REG = 0x08
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MAX31856_CJTO_REG = 0x09
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MAX31856_CJTH_REG = 0x0A
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MAX31856_CJTL_REG = 0x0B
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MAX31856_LTCBH_REG = 0x0C
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MAX31856_LTCBM_REG = 0x0D
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MAX31856_LTCBL_REG = 0x0E
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MAX31856_SR_REG = 0x0F
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MAX31856_FAULT_CJRANGE = 0x80 # Cold Junction out of range
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MAX31856_FAULT_TCRANGE = 0x40 # Thermocouple out of range
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MAX31856_FAULT_CJHIGH = 0x20 # Cold Junction High
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MAX31856_FAULT_CJLOW = 0x10 # Cold Junction Low
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MAX31856_FAULT_TCHIGH = 0x08 # Thermocouple Low
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MAX31856_FAULT_TCLOW = 0x04 # Thermocouple Low
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MAX31856_FAULT_OVUV = 0x02 # Under Over Voltage
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MAX31856_FAULT_OPEN = 0x01
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MAX31856_SCALE = 5
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MAX31856_MULT = 0.0078125
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class MAX31856(SensorBase):
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def __init__(self, config):
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SensorBase.__init__(self, config, TS_CHIP_MAX31856,
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self.build_spi_init(config))
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def calc_temp(self, adc, fault):
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if fault & MAX31856_FAULT_CJRANGE:
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self.fault("Max31856: Cold Junction Range Fault")
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if fault & MAX31856_FAULT_TCRANGE:
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self.fault("Max31856: Thermocouple Range Fault")
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if fault & MAX31856_FAULT_CJHIGH:
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self.fault("Max31856: Cold Junction High Fault")
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if fault & MAX31856_FAULT_CJLOW:
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self.fault("Max31856: Cold Junction Low Fault")
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if fault & MAX31856_FAULT_TCHIGH:
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self.fault("Max31856: Thermocouple High Fault")
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if fault & MAX31856_FAULT_TCLOW:
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self.fault("Max31856: Thermocouple Low Fault")
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if fault & MAX31856_FAULT_OVUV:
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self.fault("Max31856: Over/Under Voltage Fault")
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if fault & MAX31856_FAULT_OPEN:
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self.fault("Max31856: Thermocouple Open Fault")
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adc = adc >> MAX31856_SCALE
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# Fix sign bit:
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if adc & 0x40000:
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adc = ((adc & 0x3FFFF) + 1) * -1
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temp = MAX31856_MULT * adc
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return temp
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def calc_adc(self, temp):
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adc = int( ( temp / MAX31856_MULT ) + 0.5 ) # convert to ADC value
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adc = adc << MAX31856_SCALE
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return adc
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def build_spi_init(self, config):
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cmds = []
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value = MAX31856_CR0_AUTOCONVERT
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if config.getboolean('tc_use_50Hz_filter', False):
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value |= MAX31856_CR0_FILT50HZ
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cmds.append(0x80 + MAX31856_CR0_REG)
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cmds.append(value)
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types = {
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"B" : 0b0000,
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"E" : 0b0001,
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"J" : 0b0010,
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"K" : 0b0011,
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"N" : 0b0100,
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"R" : 0b0101,
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"S" : 0b0110,
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"T" : 0b0111,
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}
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value = config.getchoice('tc_type', types, default="K")
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averages = {
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"1" : MAX31856_CR1_AVGSEL1,
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"2" : MAX31856_CR1_AVGSEL2,
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"4" : MAX31856_CR1_AVGSEL4,
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"8" : MAX31856_CR1_AVGSEL8,
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"16" : MAX31856_CR1_AVGSEL16
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}
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value |= config.getchoice('tc_averaging_count', averages, "1")
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cmds.append(0x80 + MAX31856_CR1_REG)
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cmds.append(value)
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value = (MAX31856_MASK_VOLTAGE_UNDER_OVER_FAULT |
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MAX31856_MASK_THERMOCOUPLE_OPEN_FAULT)
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cmds.append(0x80 + MAX31856_MASK_REG)
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cmds.append(value)
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return cmds
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######################################################################
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# MAX31855 thermocouple
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######################################################################
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MAX31855_SCALE = 18
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MAX31855_MULT = 0.25
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class MAX31855(SensorBase):
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def __init__(self, config):
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SensorBase.__init__(self, config, TS_CHIP_MAX31855)
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def calc_temp(self, adc, fault):
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if adc & 0x1:
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self.fault("MAX31855 : Open Circuit")
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if adc & 0x2:
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self.fault("MAX31855 : Short to GND")
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if adc & 0x4:
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self.fault("MAX31855 : Short to Vcc")
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adc = adc >> MAX31855_SCALE
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# Fix sign bit:
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if adc & 0x2000:
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adc = ((adc & 0x1FFF) + 1) * -1
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temp = MAX31855_MULT * adc
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return temp
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def calc_adc(self, temp):
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adc = int( ( temp / MAX31855_MULT ) + 0.5 ) # convert to ADC value
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adc = adc << MAX31855_SCALE
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return adc
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######################################################################
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# MAX6675 thermocouple
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######################################################################
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MAX6675_SCALE = 3
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MAX6675_MULT = 0.25
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class MAX6675(SensorBase):
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def __init__(self, config):
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SensorBase.__init__(self, config, TS_CHIP_MAX6675)
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def calc_temp(self, adc, fault):
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if adc & 0x02:
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self.fault("Max6675 : Device ID error")
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if adc & 0x04:
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self.fault("Max6675 : Thermocouple Open Fault")
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adc = adc >> MAX6675_SCALE
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# Fix sign bit:
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if adc & 0x2000:
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adc = ((adc & 0x1FFF) + 1) * -1
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temp = MAX6675_MULT * adc
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return temp
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def calc_adc(self, temp):
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adc = int( ( temp / MAX6675_MULT ) + 0.5 ) # convert to ADC value
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adc = adc << MAX6675_SCALE
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return adc
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######################################################################
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# MAX31865 (RTD sensor)
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######################################################################
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MAX31865_CONFIG_REG = 0x00
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MAX31865_RTDMSB_REG = 0x01
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MAX31865_RTDLSB_REG = 0x02
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MAX31865_HFAULTMSB_REG = 0x03
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MAX31865_HFAULTLSB_REG = 0x04
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MAX31865_LFAULTMSB_REG = 0x05
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MAX31865_LFAULTLSB_REG = 0x06
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MAX31865_FAULTSTAT_REG = 0x07
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MAX31865_CONFIG_BIAS = 0x80
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MAX31865_CONFIG_MODEAUTO = 0x40
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MAX31865_CONFIG_1SHOT = 0x20
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MAX31865_CONFIG_3WIRE = 0x10
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MAX31865_CONFIG_FAULTCLEAR = 0x02
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MAX31865_CONFIG_FILT50HZ = 0x01
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MAX31865_FAULT_HIGHTHRESH = 0x80
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MAX31865_FAULT_LOWTHRESH = 0x40
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MAX31865_FAULT_REFINLOW = 0x20
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MAX31865_FAULT_REFINHIGH = 0x10
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MAX31865_FAULT_RTDINLOW = 0x08
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MAX31865_FAULT_OVUV = 0x04
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VAL_A = 0.00390830
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VAL_B = 0.0000005775
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VAL_C = -0.00000000000418301
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VAL_ADC_MAX = 32768.0 # 2^15
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class MAX31865(SensorBase):
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def __init__(self, config):
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self.rtd_nominal_r = config.getint('rtd_nominal_r', 100)
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self.reference_r = config.getfloat('rtd_reference_r', 430., above=0.)
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SensorBase.__init__(self, config, TS_CHIP_MAX31865,
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self.build_spi_init(config))
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def calc_temp(self, adc, fault):
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if fault & 0x80:
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self.fault("Max31865 RTD input is disconnected")
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if fault & 0x40:
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self.fault("Max31865 RTD input is shorted")
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if fault & 0x20:
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self.fault("Max31865 VREF- is greater than 0.85 * VBIAS, FORCE- open")
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if fault & 0x10:
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self.fault("Max31865 VREF- is less than 0.85 * VBIAS, FORCE- open")
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if fault & 0x08:
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self.fault("Max31865 VRTD- is less than 0.85 * VBIAS, FORCE- open")
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if fault & 0x04:
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self.fault("Max31865 Overvoltage or undervoltage fault")
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if fault & 0x03:
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self.fault("Max31865 Unspecified error")
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adc = adc >> 1 # remove fault bit
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R_rtd = (self.reference_r * adc) / VAL_ADC_MAX
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temp = (
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(( ( -1 * self.rtd_nominal_r ) * VAL_A ) +
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math.sqrt( ( self.rtd_nominal_r * self.rtd_nominal_r * VAL_A * VAL_A ) -
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( 4 * self.rtd_nominal_r * VAL_B * ( self.rtd_nominal_r - R_rtd ) )))
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/ (2 * self.rtd_nominal_r * VAL_B))
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return temp
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def calc_adc(self, temp):
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R_rtd = temp * ( 2 * self.rtd_nominal_r * VAL_B )
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R_rtd = math.pow( ( R_rtd + ( self.rtd_nominal_r * VAL_A ) ), 2)
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R_rtd = -1 * ( R_rtd - ( self.rtd_nominal_r * self.rtd_nominal_r * VAL_A * VAL_A ) )
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R_rtd = R_rtd / ( 4 * self.rtd_nominal_r * VAL_B )
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R_rtd = ( -1 * R_rtd ) + self.rtd_nominal_r
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adc = int( ( ( R_rtd * VAL_ADC_MAX ) / self.reference_r) + 0.5 )
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adc = adc << 1 # Add fault bit
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return adc
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def build_spi_init(self, config):
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value = (MAX31865_CONFIG_BIAS |
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MAX31865_CONFIG_MODEAUTO |
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MAX31865_CONFIG_FAULTCLEAR)
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if config.getboolean('rtd_use_50Hz_filter', False):
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value |= MAX31865_CONFIG_FILT50HZ
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if config.getint('rtd_num_of_wires', 2) == 3:
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value |= MAX31865_CONFIG_3WIRE
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cmd = 0x80 + MAX31865_CONFIG_REG
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return [cmd, value]
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######################################################################
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# Sensor registration
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######################################################################
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Sensors = {
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"MAX6675": MAX6675,
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"MAX31855": MAX31855,
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"MAX31856": MAX31856,
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"MAX31865": MAX31865,
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}
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def load_config(config):
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# Register sensors
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pheater = config.get_printer().lookup_object("heater")
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for name, klass in Sensors.items():
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pheater.add_sensor(name, klass)
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