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Add support for setting the range and autocalibration. Closes #1.

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* added possibility to set Range, to enable/disable Autocalibrate and to calibrate maually ( see Datasheet v 1.2 : https://www.winsen-sensor.com/d/files/MH-Z14A.pdf

* Update MHZ.cpp

* Update MHZ.cpp

* Update MHZ.h

added calibrate Span, for complete functionality but commented out , due to professional use (req. constant atmosphere with 2k, 5k or 10k ppm CO2.).
corrected the bugs in MHZ.cpp also.

* Update MHZ.cpp

Added comments for  Sensors with specific firmware.

Co-authored-by: Christoph Schultz <christoph@schultz1-christoph.de>
This commit is contained in:
Christoph Schultz 2021-01-14 22:28:47 +01:00 committed by GitHub
parent d67723a05d
commit 8a063e7c27
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 77 additions and 1 deletions
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70
MHZ.cpp
View file

@ -7,6 +7,9 @@
const int MHZ14A = 14;
const int MHZ19B = 19;
const int MHZ_2K = 1;
const int MHZ_5K = 2;
const int MHZ_10K = 3;
const unsigned long MHZ14A_PREHEATING_TIME = 3L * 60L * 1000L;
const unsigned long MHZ19B_PREHEATING_TIME = 3L * 60L * 1000L;
@ -251,3 +254,70 @@ int MHZ::readCO2PWM() {
}
return ppm_pwm;
}
void MHZ::setAutoCalibrate(boolean b) //only available for MHZ-19B with firmware < 1.6 and MHZ 14a
{
uint8_t cmd_enableAutoCal[9] = { 0xFF, 0x01, 0x79, 0xA0, 0x00, 0x00, 0x00, 0x00, 0xE6 };
uint8_t cmd_disableAutoCal[9] = { 0xFF, 0x01, 0x79, 0x00, 0x00, 0x00, 0x00, 0x00, 0x86};
if (b)
{
_serial->write(cmd_enableAutoCal,9);
}
else
{
_serial->write(cmd_disableAutoCal,9);
}
}
void MHZ::setRange(int range) //only available for MHZ-19B < 1.6 and MH-Z 14a
{
uint8_t cmd_2K[9] = {0xFF, 0x01, 0x99, 0x00, 0x00, 0x00, 0x07, 0xD0, 0x8F};
uint8_t cmd_5K[9] = {0xFF, 0x01, 0x99, 0x00, 0x00, 0x00, 0x13, 0x88, 0xCB};
uint8_t cmd_10K[9] = {0xFF, 0x01, 0x99, 0x00, 0x00, 0x00, 0x27, 0x10, 0x2F};
switch(range)
{
case 1:
_serial->write(cmd_2K,9);
break;
case 2:
_serial->write(cmd_5K,9);
break;
case 3:
_serial->write(cmd_10K,9);
}
}
void MHZ::calibrateZero()
{
char cmd[9] = {0xFF, 0x01, 0x87, 0x00, 0x00, 0x00, 0x00, 0x00, 0x78};
_serial->write(cmd,9);
}
/***** calibrateSpan() function for professional use. requires a constant atmosphere with 2K, 5k or 10k ppm CO2 and calibrateZero at first.
void MHZ::calibrateSpan(int range)
{
char cmd_2K[9] = {0xFF, 0x01, 0x88, 0x07, 0xD0, 0x00, 0x00, 0x00, 0xA0};
char cmd_5K[9] = {oxFF, 0x01, 0x88, 0x13, 0x88, 0x00, 0x00, 0x00, 0xDC};
char cmd_10K[9]= {0xFF, 0x01, 0x88, 0x27, 0x10, 0x00, 0x00, 0x00, 0x40};
switch(range)
{
case 1:
_serial->write(cmd_2K,9);
break;
case 2:
_serial->write(cmd_5K,9);
break;
case 3:
_serial->write(cmd_10k,9);
}
}
****/

8
MHZ.h
View file

@ -16,7 +16,9 @@
// types of sensors.
extern const int MHZ14A;
extern const int MHZ19B;
extern const int MHZ_2K;
extern const int MHZ_5k;
extern const int MHZ_10K;
// status codes
extern const int STATUS_NO_RESPONSE;
extern const int STATUS_CHECKSUM_MISMATCH;
@ -35,6 +37,10 @@ class MHZ {
boolean isPreHeating();
boolean isReady();
void setAutoCalibrate(boolean b);
void calibrateZero();
void setRange(int range);
// void calibrateSpan(int range); //only for professional use... see implementation and Dataheet.
int readCO2UART();
int readCO2PWM();