SalinityController.cpp

00001 #include "SalinityController.h"
00002 
00003 static AnalogIn salinity_sensor(p19);
00004 static DigitalOut alarmled(LED2);
00005 
00006 //Read the sensor, update the local variable.
00007 void SalinityController::update() {
00008     this->salinity = SalinityController::getAdjustedPPT();
00009 }
00010 
00011 //Return the value, this function does not update the value.
00012 float SalinityController::getValue() {
00013     return this->salinity;    
00014 }
00015 
00016 //Read the voltage, get an average over NUM_MEASUREMENTS values defined in settings.h
00017 float SalinityController::getVoltage() {
00018     float voltage = 0;
00019     float analogin_value = 0;
00020     
00021     // Read 0-1.0 value
00022     for(int i = 0; i < NUM_MEASUREMENTS; i++) {
00023         analogin_value += salinity_sensor.read();
00024         //Thread::wait(MEASUREMENT_DELAY);
00025     }
00026     
00027     analogin_value /= (float) NUM_MEASUREMENTS;    
00028     voltage = analogin_value * 3.3f * (5.0f/3.0f);
00029     
00030     return voltage;
00031 }
00032 
00033 //Convert inputvolt to corrected sensor value
00034 float SalinityController::voltToSensor(float inputvolt) {
00035     float slope = 0.7931723;
00036     float intercept = 0.0050561;
00037     
00038     float offset = (slope * inputvolt) - intercept;
00039     
00040     return inputvolt + offset;
00041 }
00042 
00043 //Convert corrected sensor value to actual PPT
00044 float SalinityController::sensorToPPT(float inputvolt) {
00045     float slope = 11.53368;
00046     float intercept = 0.43580;    
00047     float minimum = 0.03778499;
00048     
00049     if (inputvolt <= minimum) 
00050         return 0.00;
00051     
00052     return (slope * inputvolt) - intercept;
00053 }
00054 
00055 //Chain the needed functions to get the proper PPT
00056 float SalinityController::getAdjustedPPT() {
00057   return sensorToPPT(voltToSensor(getVoltage()));   
00058 }
00059 
00060 
00061 std::string SalinityController::getName() {
00062     return "SalinityController";
00063 }
00064 
00065 void SalinityController::setLed(bool value){
00066     if (value) alarmled = 1;
00067     if (!value) alarmled = 0;
00068 }