mass_flow_meter.h File Reference

Mass flow meter management. More...

#include <Arduino.h>

Go to the source code of this file.

Macros
#define	MFM_CALIBRATION_OK   0
#define	MFM_CALIBRATION_IMPOSSIBLE   1
#define	MFM_CALIBRATION_OUT_OF_RANGE   2
#define	MFM_SFM_3300D_I2C_ADDRESS   0x40
#define	MFM_HONEYWELL_HAF_I2C_ADDRESS   0x49
#define	MFM_SDP703_02_I2C_ADDRESS   0x40
#define	MFM_SFM3019_I2C_ADDRESS   0x2E
#define	MFM_FORCE_RELEASE_I2C_TRUE   0xb00b
#define	MFM_FORCE_RELEASE_I2C_FALSE   0

Functions
bool	MFM_init (void)
	Initialize Mass Flow Meter. More...
int32_t	MFM_read_milliliters (bool reset_after_read)
	Get the number of milliliters since last reset. More...
int32_t	MFM_expi_read_milliliters (bool reset_after_read)
	Get the number of milliliters since last reset for expiratory sensor. More...
void	MFM_reset (void)
	Reset the volume counter. More...
int8_t	MFM_calibrateZero (void)
	Calibrate the zero of the sensor. More...
int32_t	MFM_getOffset (void)
	Get massflow meter offset. More...
int32_t	MFM_read_airflow (void)
	Read instant air flow. More...
int32_t	MFM_expi_read_airflow (void)
	Read instant air flow. More...
uint32_t	MFM_read_serial_number (void)
	Get the serial number of the inspiratory flow meter. More...
uint32_t	MFM_expi_read_serial_number (void)
	Get the serial number of the expiratory flow meter. More...

Variables
volatile uint16_t	MFM_force_release_I2C

Detailed Description

Mass flow meter management.

Author

Makers For Life

Copyright

Copyright (c) 2020 Makers For Life

Definition in file mass_flow_meter.h.

Macro Definition Documentation

MFM_CALIBRATION_IMPOSSIBLE

#define MFM_CALIBRATION_IMPOSSIBLE   1

Definition at line 51 of file mass_flow_meter.h.

MFM_CALIBRATION_OK

#define MFM_CALIBRATION_OK   0

Definition at line 50 of file mass_flow_meter.h.

MFM_CALIBRATION_OUT_OF_RANGE

#define MFM_CALIBRATION_OUT_OF_RANGE   2

Definition at line 52 of file mass_flow_meter.h.

MFM_FORCE_RELEASE_I2C_FALSE

#define MFM_FORCE_RELEASE_I2C_FALSE   0

Definition at line 91 of file mass_flow_meter.h.

MFM_FORCE_RELEASE_I2C_TRUE

#define MFM_FORCE_RELEASE_I2C_TRUE   0xb00b

Definition at line 90 of file mass_flow_meter.h.

MFM_HONEYWELL_HAF_I2C_ADDRESS

#define MFM_HONEYWELL_HAF_I2C_ADDRESS   0x49

Definition at line 84 of file mass_flow_meter.h.

MFM_SDP703_02_I2C_ADDRESS

#define MFM_SDP703_02_I2C_ADDRESS   0x40

Definition at line 85 of file mass_flow_meter.h.

MFM_SFM3019_I2C_ADDRESS

#define MFM_SFM3019_I2C_ADDRESS   0x2E

Definition at line 86 of file mass_flow_meter.h.

MFM_SFM_3300D_I2C_ADDRESS

#define MFM_SFM_3300D_I2C_ADDRESS   0x40

Definition at line 83 of file mass_flow_meter.h.

Function Documentation

MFM_calibrateZero()

int8_t MFM_calibrateZero

(

void

)

Calibrate the zero of the sensor.

Returns

One of:

• MFM_CALIBRATION_OK: all right
• MFM_CALIBRATION_IMPOSSIBLE: communication problem
• MFM_CALIBRATION_OUT_OF_RANGE: unbelievable 10SLPM sensor drift; time to change it?

Note

This uses the mean of 10 samples

Calibrate the zero of the sensor.

Definition at line 604 of file mass_flow_meter.cpp.

                               {
    int8_t ret = MFM_CALIBRATION_OK;
    // activate table fill with last valid value
    mfmInspiratoryInstantAirFlowLastValuesIndex = 0;
    mfmInspiratoryInstantAirFlowRecord = true;
    // wait for the table to fill in
    delay(2 + (MFM_MEAN_SAMPLES * (MASS_FLOW_PERIOD / 10)));
    // Check that table is full (record must be false)
    // If it is not, there is a sensor problem
    // In case of problem, do not update mfmInspiratoryCalibrationOffset
    if (!mfmInspiratoryInstantAirFlowRecord) {
        int32_t zeroFlow = 0;
        for (int16_t i = 0; i < MFM_MEAN_SAMPLES; i++) {
            zeroFlow += mfmInspiratoryInstantAirFlowLastValues[i];
        }
        zeroFlow /= MFM_MEAN_SAMPLES;
        // check that value is credible: [-10 10] SLPM
        if ((zeroFlow < 10000) && (zeroFlow > -10000)) {
            mfmInspiratoryCalibrationOffset = zeroFlow;
        } else {
            ret = MFM_CALIBRATION_OUT_OF_RANGE;
        }
    } else {
        ret = MFM_CALIBRATION_IMPOSSIBLE;
    }
    return ret;
}

MFM_expi_read_airflow()

int32_t MFM_expi_read_airflow

(

void

)

Read instant air flow.

Definition at line 566 of file mass_flow_meter.cpp.

                                    {
    int32_t r;
    if (mfmFaultCondition) {
        r = MASS_FLOW_ERROR_VALUE;
    } else {
        r = mfmExpiratoryInstantAirFlow - mfmExpiratoryCalibrationOffset;
    }
    return r;
}

MFM_expi_read_milliliters()

int32_t MFM_expi_read_milliliters

(

bool

reset_after_read

)

Get the number of milliliters since last reset for expiratory sensor.

Parameters

reset_after_read

If true, performs the volume reset in the same atomic operation

Returns

Volume of air that went through sensor since last reset in mL

Definition at line 654 of file mass_flow_meter.cpp.

                                                         {
    int32_t result = MASS_FLOW_ERROR_VALUE;
 
#if MASS_FLOW_METER_SENSOR_EXPI == MFM_SFM_3300D
    result = mfmFaultCondition
                 ? MASS_FLOW_ERROR_VALUE
                 : ((mfmExpiratoryAirVolumeSumMilliliters * MASS_FLOW_PERIOD) / (60 * 10000));
#endif
    if (reset_after_read) {
        MFM_expi_reset();
    }
 
    return result;
}

MFM_expi_read_serial_number()

uint32_t MFM_expi_read_serial_number

(

void

)

Get the serial number of the expiratory flow meter.

Returns

The serial number, or 0 if before init or if init failed

Get the serial number of the expiratory flow meter.

Note

returns 0 before init, or if init failed.

Definition at line 597 of file mass_flow_meter.cpp.

{ return mfmSfm3300SerialNumberExpi; }

MFM_getOffset()

int32_t MFM_getOffset

(

void

)

Get massflow meter offset.

Definition at line 635 of file mass_flow_meter.cpp.

{ return mfmInspiratoryCalibrationOffset; }

MFM_init()

bool MFM_init

(

void

)

Initialize Mass Flow Meter.

Returns

True if there is a Mass Flow Meter connected

Warning

If no Mass Flow Meter is detected, you will always read volume = 0 mL

Definition at line 321 of file mass_flow_meter.cpp.

                    {
    mfmInspiratoryAirVolumeSumMilliliters = 0;
    // cppcheck-suppress unreadVariable
    uint32_t errorCount = 0;
    // Set power on (hardware v3)
    pinMode(MFM_POWER_CONTROL, OUTPUT);
    digitalWrite(MFM_POWER_CONTROL, MFM_POWER_ON);
    delay(100);  // sfm3300 worst case boot time.
 
    // Set the timer
    massFlowTimer = new HardwareTimer(MASS_FLOW_TIMER);
 
    // Prescaler; stm32f411 clock is 100 mHz
    massFlowTimer->setPrescaleFactor((massFlowTimer->getTimerClkFreq() / MASS_FLOW_TIMER_FREQ) - 1);
 
    // Set the period
    massFlowTimer->setOverflow(MASS_FLOW_PERIOD);
    massFlowTimer->setMode(MASS_FLOW_CHANNEL, TIMER_OUTPUT_COMPARE, NC);
    massFlowTimer->attachInterrupt(MFM_Timer_Callback);
 
    // Interrupt priority is documented here:
    // https://stm32f4-discovery.net/2014/05/stm32f4-stm32f429-nvic-or-nested-vector-interrupt-controller/
    // WARNING : since 1.9.0 lib, I2C is on level 2. must be under...
    massFlowTimer->setInterruptPriority(3, 0);
 
    // default Wire instance is on PB8 BP9, anyway
    Wire.setSDA(PIN_I2C_SDA);
    Wire.setSCL(PIN_I2C_SCL);
    // Wire.setClock(400000); // honeywell do support, but no information about sfm3300d
 
#if MASS_FLOW_METER_SENSOR == MFM_SFM3019
    Wire.begin();
    Wire.beginTransmission(0x00);
    Wire.write(0x06);
    Wire.endTransmission();
    Wire.end();
    delay(4);
 
    //     // start air continuous measurement
    //     Wire.begin();
    //     Wire.beginTransmission(MFM_SFM3019_I2C_ADDRESS);
    //     Wire.write(0x36);
    //     Wire.write(0x08);
    //     errorCount += Wire.endTransmission();
    //     Wire.end();
 
    //     delay(2);
    //     //Stop continuous measurement 0x3FF9
    //     Wire.begin();
    //     Wire.beginTransmission(0x2E);
    //     Wire.write(0x3F);
    //     Wire.write(0xF9);
    //     Wire.endTransmission();
    //     Wire.end();
 
    //     delay(2);
    //      //Read Scale Factor, Offset, and Flow Unit 0x3661
    //     Wire.begin();
    //     Wire.beginTransmission(0x2E);
    //     Wire.write(0x36);
    //     Wire.write(0x61);
    //     Wire.endTransmission();
    //     Wire.end();
    // delay(2);
    //     Wire.begin();
    //     int ccc = Wire.requestFrom(0x2E, 8);
    //     Serial.print(ccc);
    //     Serial.print(" ");
    //     Serial.print(Wire.read()); Serial.print(",");
    //     Serial.print(Wire.read()); Serial.print(",");
    //     Serial.print(Wire.read()); Serial.print(",");
    //     Serial.print(Wire.read()); Serial.print(",");
    //     Serial.print(Wire.read()); Serial.print(",");
    //     Serial.print(Wire.read()); Serial.print(",");
    //     Serial.print(Wire.read()); Serial.print(",");
    //     Serial.print(Wire.read()); Serial.print(",");
 
    //     Wire.end();
 
    delay(5);
    // Read serial number
    Wire.begin();
    Wire.beginTransmission(MFM_SFM3019_I2C_ADDRESS);
    Wire.write(0xE1);
    Wire.write(0x02);
    errorCount = Wire.endTransmission();
 
    delay(1);
    errorCount += ((18u == Wire.requestFrom(MFM_SFM3019_I2C_ADDRESS, 18)) ? 0u : 1u);
    if (errorCount == 0u) {
        // the serial number is 64 bits wide, but it will never be used until year 2042.
        // The serial number can be converted from binary into decimal,
        // whereby in decimal it has the following format::
        // yywwxxxxxx, where: yy: last to digits of calibration year, ww:
        // calibration week, xxxxxx: unique 6-digit sequential number
        // within the calibration week.
        uint32_t sn_inspi = 0;
        Wire.read();
        Wire.read();  // product number part 1
        Wire.read();  // crc
        Wire.read();
        Wire.read();  // product number part 2
        Wire.read();  // crc
 
        Wire.read();
        Wire.read();  // ignore this part of serial
        Wire.read();  // ignore inlined crc
        Wire.read();
        Wire.read();  // ignore this part of serial
        Wire.read();  // ignore inlined crc
        sn_inspi |= Wire.read();
        sn_inspi <<= 8;
        sn_inspi |= Wire.read();
        sn_inspi <<= 8;
        Wire.read();  // ignore inlined crc
        sn_inspi |= Wire.read();
        sn_inspi <<= 8;
        sn_inspi |= Wire.read();
        Wire.read();  // ignore inlined crc
        mfmSfm3019SerialNumber = sn_inspi;
    }
    delay(1);
 
    // start air continuous measurement
    Wire.begin();
    Wire.beginTransmission(MFM_SFM3019_I2C_ADDRESS);
    Wire.write(0x36);
    Wire.write(0x08);
    errorCount += Wire.endTransmission();
    Wire.end();
 
    delay(40);  // the first measurement result will be available after 12ms
    // small accuracy deviations (few % of reading) can occur during the first 30ms
 
    // delay(10000);
    if (errorCount != 0u) {
        mfmFaultCondition = true;
        mfmResetStateMachine = MFM_WAIT_RESET_PERIODS;
    }
#endif
 
#if MASS_FLOW_METER_SENSOR_EXPI == MFM_SFM_3300D
    Wire.begin();  // Join I2C bus (address is optional for master)
    Wire.beginTransmission(MFM_SFM_3300D_I2C_ADDRESS);
    Wire.write(0x20);  // 0x2000 soft reset
    Wire.write(0x00);
    errorCount = Wire.endTransmission();
    delay(5);  // end of reset
 
    Wire.beginTransmission(MFM_SFM_3300D_I2C_ADDRESS);
    Wire.write(0x31);  // 0x31AE read serial
    Wire.write(0xAE);
    errorCount += Wire.endTransmission();
 
    errorCount += ((6u == Wire.requestFrom(MFM_SFM_3300D_I2C_ADDRESS, 6)) ? 0u : 1u);
    if (errorCount == 0u) {
        u_int32_t sn_expi = 0;
        sn_expi = Wire.read();
        sn_expi <<= 8;
        sn_expi |= Wire.read();
        sn_expi <<= 8;
        Wire.read();  // ignore inlined crc
        sn_expi |= Wire.read();
        sn_expi <<= 8;
        sn_expi |= Wire.read();
        Wire.read();  // ignore inlined crc
        mfmSfm3300SerialNumberExpi = sn_expi;
    }
    delay(10);
    Wire.beginTransmission(MFM_SFM_3300D_I2C_ADDRESS);
    Wire.write(0x10);  // 0x1000 start measurement
    Wire.write(0x00);
    errorCount += Wire.endTransmission();
    Wire.end();
    delay(100);  // wait 100ms before having available data.
 
    if (errorCount != 0u) {
        mfmFaultCondition = true;
        mfmResetStateMachine = MFM_WAIT_RESET_PERIODS;
    }
#endif
 
#if MASS_FLOW_METER_SENSOR == MFM_HONEYWELL_HAF
 
    /*
    Init sequence for Honeywell Zephyr mass flow sensor:
    1st read operation: the sensor will send 0x0000
    2nd read operation: the sensor will send the first part of the serial number
    3rd read operation: the sensor will send the second part of the serial number
    Subsequent read operations: the sensor will send calibrated mass air flow values with two
    leading 0
    */
    Wire.begin();
    Wire.beginTransmission(MFM_HONEYWELL_HAF_I2C_ADDRESS);
    Wire.write(0x02);  // Force reset
    uint8_t txOk = Wire.endTransmission();
    Wire.end();
    delay(30);
 
    u_int32_t sn = 0;
    Wire.begin();
    Wire.beginTransmission(MFM_HONEYWELL_HAF_I2C_ADDRESS);
    uint8_t rxcount = Wire.requestFrom(MFM_HONEYWELL_HAF_I2C_ADDRESS, 2);
    sn = Wire.read();
    sn <<= 8;
    sn |= Wire.read();  // first transmission is serial number register 0
    sn <<= 8;
    delay(2);  // if you do not wait, sensor will send again register 0
    rxcount += Wire.requestFrom(MFM_HONEYWELL_HAF_I2C_ADDRESS, 2);
    sn |= Wire.read();
    sn <<= 8;
    sn |= Wire.read();  // second transmission is serial number register 1
 
    if ((txOk != 0u) || (rxcount != 4u)) {  // If transmission failed
        mfmFaultCondition = true;
        mfmResetStateMachine = MFM_WAIT_RESET_PERIODS;
    } else {
        mfmHoneywellHafSerialNumber = sn;
    }
    Wire.end();
 
#if MODE == MODE_MFM_TESTS
    Serial.println("Read 1");
    Serial.println(mfmLastData.i);
    Serial.println("fault condition:");
    Serial.println(mfmFaultCondition ? "failure" : "no failure");
#endif
    delay(100);
#endif
 
    massFlowTimer->resume();
    return !mfmFaultCondition;
}

MFM_read_airflow()

int32_t MFM_read_airflow

(

void

)

Read instant air flow.

Definition at line 555 of file mass_flow_meter.cpp.

                               {
    int32_t r;
    if (mfmFaultCondition) {
        r = MASS_FLOW_ERROR_VALUE;
    } else {
        r = mfmInspiratoryInstantAirFlow - mfmInspiratoryCalibrationOffset;
    }
    return r;
}

MFM_read_milliliters()

int32_t MFM_read_milliliters

(

bool

reset_after_read

)

Get the number of milliliters since last reset.

Parameters

reset_after_read

If true, performs the volume reset in the same atomic operation

Returns

Volume of air that went through sensor since last reset in mL

Definition at line 637 of file mass_flow_meter.cpp.

                                                    {
    int32_t result = MASS_FLOW_ERROR_VALUE;
 
#if MASS_FLOW_METER_SENSOR == MFM_HONEYWELL_HAF || MASS_FLOW_METER_SENSOR == MFM_SFM3019
    // period is MASS_FLOW_PERIOD / 10000  (100 µs prescaler)
    result = mfmFaultCondition
                 ? MASS_FLOW_ERROR_VALUE
                 : ((mfmInspiratoryAirVolumeSumMilliliters * MASS_FLOW_PERIOD) / (60 * 10000));
#endif
 
    if (reset_after_read) {
        MFM_reset();
    }
 
    return result;
}

MFM_read_serial_number()

uint32_t MFM_read_serial_number

(

void

)

Get the serial number of the inspiratory flow meter.

Returns

The serial number, or 0 if before init or if init failed

Definition at line 581 of file mass_flow_meter.cpp.

                                      {
#if MASS_FLOW_METER_SENSOR == MFM_HONEYWELL_HAF
    return mfmHoneywellHafSerialNumber;
#elif MASS_FLOW_METER_SENSOR == MFM_SFM3019
    return mfmSfm3019SerialNumber;
#endif
    return 0;
}

MFM_reset()

void MFM_reset

(

void

)

Reset the volume counter.

Definition at line 576 of file mass_flow_meter.cpp.

{ mfmInspiratoryAirVolumeSumMilliliters = 0; }

Variable Documentation

MFM_force_release_I2C

volatile uint16_t MFM_force_release_I2C

extern

Definition at line 32 of file mass_flow_meter.cpp.