Library for the MAX31856
The MAX31856 thermocouple temperature sensor accurately measures temperature and provides a vast amount of features such as: //FEATURE //FEATURE //FEATURE //FEATURE //FEATURE //FEATURE Communication is through an SPI-compatible interface. More...

#include <MAX31856.h>

Public Member Functions
	MAX31856 (SPI &_spi, PinName _ncs, uint8_t _type=CR1_TC_TYPE_K, uint8_t _fltr=CR0_FILTER_OUT_60Hz, uint8_t _samples=CR1_AVG_TC_SAMPLES_1, uint8_t _conversion_mode=CR0_CONV_MODE_NORMALLY_OFF)
	Constructor to create MAX31856 object with SPI information as well as preconfiguration parameter settings in configuration registers Zero and One.
	~MAX31856 (void)
	Destructor.
float	readTC ()
	Requests read of the thermocouple temperature.
float	readCJ ()
	Requests read of the cold junction temperature.
bool	setConversionMode (uint8_t val)
	Sets bits in the configuration register zero for setting the rate of conversions.
bool	setOneShotMode (uint8_t val)
	Sets bits in the configuration register zero for enabling one conversion to take place.
bool	setOpenCircuitFaultDetection (uint8_t val)
	Sets bits in the configuration register zero for configuring open circuit fault detection.
bool	setColdJunctionDisable (uint8_t val)
	Sets bits in the configuration register zero for disabling or enabling the Cold Junction.
bool	setFaultMode (uint8_t val)
	Sets bits in the configuration register zero for setting fault mode status.
bool	setFaultStatusClear (uint8_t val)
	Sets bits in the configuration register zero for clearing fault status.
bool	setEmiFilterFreq (uint8_t val)
	Sets bits in the configuration register zero for setting which of the two filter modes either 50Hz or 60Hz cancelation.
bool	setNumSamplesAvg (uint8_t val)
	Sets bits in the configuration register one for setting how many readings are taken.
bool	setThermocoupleType (uint8_t val)
	Sets bits in the configuration register one for setting which thermocouple type is going to be programmed into the MAX31856 for linearization of thermovoltage produced and temperature.
bool	setFaultMasks (uint8_t val, bool enable)
	Sets bits in the configuration register one for setting fault masks.
bool	setFaultThresholds (uint8_t val, float temperature)
	Sets bits in the configuration register one for setting thresholds that corespond to the fault mask settings.
uint8_t	checkFaultsThermocoupleThresholds ()
	Check the fault stautus register to see if there is anything wrong with range of thermocouple temperature whether outside opperating temperatures or if above/below thresholds that are set.
uint8_t	checkFaultsColdJunctionThresholds ()
	Check the fault stautus register to see if there is anything wrong with range of cold junction temperature whether outside opperating temperatures or if above/below thresholds that are set.
bool	checkFaultsThermocoupleConnection ()
	Check the fault stautus register to see if there is anything wrong with thermocouple connection to the MAX31856.
bool	registerReadWriteByte (uint8_t read_address, uint8_t write_address, int clear_bits, uint8_t val)
	This function is to read current contents of register, manipulate the contents, then rewrite the specific register .
bool	registerWriteByte (uint8_t write_address, uint8_t val)
	This function is to read current contents of register, manipulate the contents, then rewrite the specific register .
uint8_t	registerReadByte (uint8_t read_address)
	This function is to read current contents of register by passing in the address of the read address and return contents of the register.
bool	coldJunctionOffset (float temperature)
	This function is to read current contents of register by passing in the address of the read address and return contents of the register.

Detailed Description

Library for the MAX31856
The MAX31856 thermocouple temperature sensor accurately measures temperature and provides a vast amount of features such as: //FEATURE //FEATURE //FEATURE //FEATURE //FEATURE //FEATURE Communication is through an SPI-compatible interface.

 #include "mbed.h"
 #include "MAX31856.h"
 

 // Hardware serial port 
 Serial serial(USBTX, USBRX);
 
 //SPI communications
 SPI spi(SPIO MOSI,SPIO MISO,SPIO SCK);
 
 //Thermocouples
 MAX31856 Thermocouple1(spi, CHIPSELECT);
 
 
 int main(void) 
 {
      float temperature_TC_1, temperature_CJ_1;
      while(true)
      {
          temperature_TC_1=Thermocouple1.readTC();
          temperature_CJ_1=Thermocouple1.readCJ();
          serial.printf("MAX31856 TC = %f Celsius   MAX31856 CJ = %f Celsius  \n\r",temperature_TC_1,temperature_CJ_1);
          wait(1.0);
      }
 }

Please see pages 18-26 in the MAX31856 data sheet to see what register bit masks are needed to be set to achieve functionality desired. The data sheet can be found at

https://datasheets.maximintegrated.com/en/ds/MAX31856.pdf *** MAX31856 Class

Definition at line 227 of file MAX31856.h.

Constructor & Destructor Documentation

MAX31856	(	SPI &	_spi,
		PinName	_ncs,
		uint8_t	_type = `CR1_TC_TYPE_K`,
		uint8_t	_fltr = `CR0_FILTER_OUT_60Hz`,
		uint8_t	_samples = `CR1_AVG_TC_SAMPLES_1`,
		uint8_t	_conversion_mode = `CR0_CONV_MODE_NORMALLY_OFF`
	)

Constructor to create MAX31856 object with SPI information as well as preconfiguration parameter settings in configuration registers Zero and One.

Parameters:

_spi	- Reference to SPI object
_ncs	- Chip Select for SPI comunications with the oject
_type	- Type of thermocouple used
_fltr	- Feature of the MAX31856 to filter out either 50Hz/60Hz from signal
_samples	- How many samples are averaged for one conversion
_conversion_mode	- Choose between always on and making conversions and off in between requests for a reading

Definition at line 54 of file MAX31856.cpp.

~MAX31856 ( void )

Destructor.

Definition at line 659 of file MAX31856.cpp.

Member Function Documentation

uint8_t checkFaultsColdJunctionThresholds ( )

Check the fault stautus register to see if there is anything wrong with range of cold junction temperature whether outside opperating temperatures or if above/below thresholds that are set.

Returns:

0 if no faults are present
1 if Cold Junction temp is higher than the threshold
2 if Cold Junction temp is lower than the threshold
3 if Cold Junction temp is outside operating range of termocouple type
4 if Cold Junction temp is higher than the threshold && is outside operating range of termocouple type
5 if Cold Junction temp is lower than the threshold && is outside operating range of termocouple type

Definition at line 170 of file MAX31856.cpp.

bool checkFaultsThermocoupleConnection ( )

Check the fault stautus register to see if there is anything wrong with thermocouple connection to the MAX31856.

Returns:

1 if no faults are present
0 if there is a fault and there needs to be information printed to the console to help diagnose issues

Definition at line 209 of file MAX31856.cpp.

uint8_t checkFaultsThermocoupleThresholds ( )

Check the fault stautus register to see if there is anything wrong with range of thermocouple temperature whether outside opperating temperatures or if above/below thresholds that are set.

Returns:

0 if no faults are present
1 if Thermocouple temp is higher than the threshold
2 if Thermocouple temp is lower than the threshold
3 if Thermocouple temp is outside operating range of termocouple type
4 if Thermocouple temp is higher than the threshold && is outside operating range of termocouple type
5 if Thermocouple temp is lower than the threshold && is outside operating range of termocouple type

Definition at line 131 of file MAX31856.cpp.

bool coldJunctionOffset ( float temperature )

This function is to read current contents of register by passing in the address of the read address and return contents of the register.

Parameters:

temperature - Float of value to offest the value of the cold junction offset by (must be between -8°C to +7.9375°C)

Returns:

1 on successfully updated coldjunction offset
0 if parameter temperature does not fall between range -8°C to +7.9375°C

Definition at line 558 of file MAX31856.cpp.

float readCJ ( )

Requests read of the cold junction temperature.

Returns:: float of the converted artificial cold junction reading based on current configurations

Definition at line 108 of file MAX31856.cpp.

float readTC ( )

Requests read of the thermocouple temperature.

Returns:: float of the converted thermocouple reading based on current configurations

Definition at line 64 of file MAX31856.cpp.

uint8_t registerReadByte ( uint8_t read_address )

This function is to read current contents of register by passing in the address of the read address and return contents of the register.

Parameters:

read_address - Address of register to read data from

Returns:

byte contained in the address

Definition at line 625 of file MAX31856.cpp.

bool registerReadWriteByte	(	uint8_t	read_address,
		uint8_t	write_address,
		int	clear_bits,
		uint8_t	val
	)

This function is to read current contents of register, manipulate the contents, then rewrite the specific register
.

Read the value of a register from contents of register matching the parameter read_address
Clear the bits needed to be changed by bitwise ANDing the read value with the 8 bit parameter clear_bits
Set the bits of interest in the 8 bit value by bitwise ORing the value from step two with parameter val

Rewrite to the register with the new 8 bit value to the register with the address with parameter write_address

Parameters:

read_address	- Address of register to read the data before it's changed
write_address	- Address of register to rewrite the changed data
clear_bits	- Parameter that is
val	- Bitfield that contains bits related to function specific settings

Returns:

1 on success

Definition at line 588 of file MAX31856.cpp.

bool registerWriteByte	(	uint8_t	write_address,
		uint8_t	val
	)

This function is to read current contents of register, manipulate the contents, then rewrite the specific register
.

Read the value of a register from contents of register matching the parameter read_address
Clear the bits needed to be changed by bitwise ANDing the read value with the 8 bit parameter clear_bits
Set the bits of interest in the 8 bit value by bitwise ORing the value from step two with parameter val

Write to the register with the new 8 bit value to the register with the address with parameter write_address

Parameters:

write_address	- Address of register to rewrite the changed data
val	- Byte of information that is going to be written to the regitser with the address that matches the parameter write_address

Returns:

1 on success

Definition at line 614 of file MAX31856.cpp.

bool setColdJunctionDisable ( uint8_t val )

Sets bits in the configuration register zero for disabling or enabling the Cold Junction.

Parameters:

val	CR0_COLD_JUNC_ENABLE (Power On Default value) CR0_COLD_JUNC_DISABLE

Returns:

1 on success
0 if there is an incorrect parameter that is passed in as parameter val

Definition at line 301 of file MAX31856.cpp.

bool setConversionMode ( uint8_t val )

Sets bits in the configuration register zero for setting the rate of conversions.

Parameters:

val	CR0_CONV_MODE_NORMALLY_OFF (Power On Default value) CR0_CONV_MODE_NORMALLY_ON

Returns:

1 on success
0 if there is an incorrect parameter that is passed in as parameter val

Definition at line 235 of file MAX31856.cpp.

bool setEmiFilterFreq ( uint8_t val )

Sets bits in the configuration register zero for setting which of the two filter modes either 50Hz or 60Hz cancelation.

Parameters:

val	CR0_FILTER_OUT_60Hz (Power On Default value) CR0_FILTER_OUT_50Hz

Returns:

1 on success
0 if there is an incorrect parameter that is passed in as parameter val

Definition at line 363 of file MAX31856.cpp.

bool setFaultMasks	(	uint8_t	val,
		bool	enable
	)

Sets bits in the configuration register one for setting fault masks.

Parameters:

val	MASK_CJ_FAULT_THRESHOLD_HIGH MASK_CJ_FAULT_THRESHOLD_LOW MASK_TC_FAULT_THRESHOLD_HIGH MASK_TC_FAULT_THRESHOLD_LOW MASK_OVER_UNDER_VOLT_FAULT MASK_OPEN_CIRCUIT_FAULT
enable	0 for disabling the mask in whichever option is selcted in parameter val 1 for enabling the mask in whichever option is selcted in parameter val

Returns:

1 on success
0 if there is an incorrect parameter that is passed in as parameter val

Definition at line 484 of file MAX31856.cpp.

bool setFaultMode ( uint8_t val )

Sets bits in the configuration register zero for setting fault mode status.

Parameters:

val	CR0_FAULT_MODE_COMPARATOR (Power On Default value) CR0_FAULT_MODE_INTERUPT

Returns:

1 on success
0 if there is an incorrect parameter that is passed in as parameter val

Definition at line 323 of file MAX31856.cpp.

bool setFaultStatusClear ( uint8_t val )

Sets bits in the configuration register zero for clearing fault status.

Parameters:

val	CR0_FAULTCLR_DEFAULT_VAL (Power On Default value) CR0_FAULTCLR_RETURN_FAULTS_TO_ZERO (This bit self clears itself to default back to CR0_FAULTCLR_DEFAULT_VAL after fault status is cleared)

Returns:

1 on success
0 if there is an incorrect parameter that is passed in as parameter val

Definition at line 343 of file MAX31856.cpp.

bool setFaultThresholds	(	uint8_t	val,
		float	temperature
	)

Sets bits in the configuration register one for setting thresholds that corespond to the fault mask settings.

Parameters:

val	MASK_CJ_FAULT_THRESHOLD_HIGH MASK_CJ_FAULT_THRESHOLD_LOW MASK_TC_FAULT_THRESHOLD_HIGH MASK_TC_FAULT_THRESHOLD_LOW
temperature	value that you want to program into a threshold register for temperatre

Returns:: return value that was programmed into the threshold register

Definition at line 522 of file MAX31856.cpp.

bool setNumSamplesAvg ( uint8_t val )

Sets bits in the configuration register one for setting how many readings are taken.

Parameters:

val	CR1_AVG_TC_SAMPLES_1 (Power On Default value) CR1_AVG_TC_SAMPLES_2 CR1_AVG_TC_SAMPLES_4 CR1_AVG_TC_SAMPLES_8 CR1_AVG_TC_SAMPLES_16

Returns:

1 on success
0 if there is an incorrect parameter that is passed in as parameter val

Definition at line 385 of file MAX31856.cpp.

bool setOneShotMode ( uint8_t val )

Sets bits in the configuration register zero for enabling one conversion to take place.

Parameters:

val	CR0_1_SHOT_MODE_NO_CONVERSION (Power On Default value) CR0_1_SHOT_MODE_ONE_CONVERSION (This bit self clears itself to default back to CR0_1_SHOT_MODE_NO_CONVERSION after singular conversion takes place)

Returns:

1 on success
0 if there is an incorrect parameter that is passed in as parameter val

Definition at line 257 of file MAX31856.cpp.

bool setOpenCircuitFaultDetection ( uint8_t val )

Sets bits in the configuration register zero for configuring open circuit fault detection.

Parameters:

val	CR0_OC_DETECT_DISABLED (Power On Default value) CR0_OC_DETECT_ENABLED_R_LESS_5k CR0_OC_DETECT_ENABLED_TC_LESS_2ms CR0_OC_DETECT_ENABLED_TC_MORE_2ms

Returns:

1 on success
0 if there is an incorrect parameter that is passed in as parameter val

Definition at line 273 of file MAX31856.cpp.

bool setThermocoupleType ( uint8_t val )

Sets bits in the configuration register one for setting which thermocouple type is going to be programmed into the MAX31856 for linearization of thermovoltage produced and temperature.

Parameters:

val	CR1_TC_TYPE_B CR1_TC_TYPE_E CR1_TC_TYPE_J CR1_TC_TYPE_K (Power On Default value) CR1_TC_TYPE_N CR1_TC_TYPE_R CR1_TC_TYPE_S CR1_TC_TYPE_T CR1_TC_TYPE_VOLT_MODE_GAIN_8 CR1_TC_TYPE_VOLT_MODE_GAIN_32

Returns:

1 on success
0 if there is an incorrect parameter that is passed in as parameter val

Definition at line 422 of file MAX31856.cpp.

Type:	Library
Created:	29 Sep 2017
Imports:	55
Forks:	0
Commits:	2
Dependents:	1
Dependencies:	0
Followers:	64

MAX31856 Class Reference

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Repository toolbox

Repository details

Important Information for this Arm website

MAX31856 Class Reference

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Repository toolbox

Repository details

Important Information for this Arm website

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