IPKM/pfg_security
3
0
Fork 0
Code

PFG security firmware initila realease

Browse Source
This commit is contained in:
Markus Rosenstihl 2017-03-08 16:47:33 +00:00
commit dfe0c803bb
1 changed files with 210 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

210
pfg_security.ino Normal file
View File

@ -0,0 +1,210 @@
#include <limits.h>
// Needed for LiquidCrystal_I2C.h
#include <Wire.h>
// from https://bitbucket.org/fmalpartida/new-liquidcrystal/downloads/
#include <LiquidCrystal_I2C.h>
// as per http://funduino.de/nr-06-zwei-i%C2%B2c-displays-gleichzeitig
LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);
boolean setup_ok=true; // false will stop loop()
const int N=16; // number of sample averages
volatile unsigned int deltas[N]; // array of time deltas between interrupt
volatile unsigned int n = 0; // run variable
unsigned long total;
float flow;
int prescaler;
char buff[10]; // temp. buffer for string manipulation/formatting
char serialbuff[16]; // temp. buffer for string manipulation/formatting
/*
User configuration
==================
Flow meter
==========
The PFG flow meter can measure from 0.24 to 17 l/min at 4 pulses/s per l/min
max period about 1s, i.e. min flow of 0.24l/min
min period about 15 ms i.e. max flow of 17l/min
The time base of the timer counter TCNT1
t_step or seconds/tick = prescaler/clock
Note: Maximum TCNT1 value is 65535, i.e.
Maximum time lengths (and thus timeouts) per prescaler value are:
8 0.0327675 s
64 0.26214 s
256 1.04856 s
1024 4.19424 s
For accuracy the prescaler is set automatically fitting to the TIMEOUT.
*/
#define TIMEOUT 1.0 // measurement timeout in Hz (needs to be less than timer1 limits above)
#define DISPLAY_INTERVAL 1.0 // display update interval (and serial send interval)
const float conversion = 4.0; // conversion factor, pulses/s per l/min
const float flow_threshold = 1.0; // alarm threshold for flow
/*
Hardware configuration / wiring setup
=====================================
Pin 13 has an LED connected on most Arduino boards.
This is the alarm LED pin
*/
#define ALARM_LED_PIN 13
// interlock output pin
#define INTERLOCK_PIN 12
/*
Setup routine
=============
Run once upon startup
*/
void setup()
{
lcd.begin(16,2); // start LCD (16x2 characters)
lcd.home (); // go home
lcd.print("PFG security"); // string first line
lcd.setCursor ( 0, 1 ); // go to the next line
lcd.print (""); // string second line
Serial.begin(19200); // serial line speed
/* Interrupt pins
UNO:
interrupt 1 is pin 3
interrupt 0 is pin 2
*/
attachInterrupt(0, get_time, FALLING);
pinMode(ALARM_LED_PIN, OUTPUT);
pinMode(INTERLOCK_PIN, OUTPUT);
/*
Set sensible default starting values for the deltas array,
otherwise the array values are maybe zero at the beginning
and we get very high (wrong) flow values.
*/
for (int k=0; k<N; k++){
deltas[k]=UINT_MAX;
}
/*
timer1 setup
*/
// select prescaler according to TIMEOUT
if (TIMEOUT < 0.0327675)
prescaler = 8;
else if (TIMEOUT < 0.26214)
prescaler = 64;
else if (TIMEOUT < 1.04856)
prescaler = 256;
else if (TIMEOUT < 4.19424)
prescaler = 1024;
else {
lcd.setCursor (0,1); // char 0 on line 0 or 1
lcd.print ("ERR TIMEOUT BIG");
setup_ok=false;
return;
}
noInterrupts(); // disable all interrupts
// clear timer1 registers
TCCR1A = 0;
TCCR1B = 0;
TCNT1 = 0; // timer1 counter, reset on every HW interrupt from the flow meter (see get_time function)
OCR1A = (int)(16e6/prescaler*TIMEOUT);// Clear timer on compare match value: 16MHz/PRESCALER*timeout(in s)
TCCR1B |= (1 << WGM12); // CTC mode (Clear Timer on Compare Match)
/*
Prescaler settings x=0,1,2 (Timer0, Timer1, Timer2)
CSx2 CSx1 CSx0 Beschreibung
0 1 0 Clk/8 (1 << CS11)
0 1 1 Clk/64 (1 << CS11)|(1 << CS10)
1 0 0 Clk/256 (1 << CS12)
1 0 1 Clk/1024 (1 << CS12)|(1 << CS10)
*/
if (prescaler == 8)
TCCR1B |= (1 << CS11);
else if (prescaler == 64)
TCCR1B |= (1 << CS11)|(1 << CS10);
else if (prescaler == 256)
TCCR1B |= (1 << CS12);
else if (prescaler == 1024)
TCCR1B |= (1 << CS12)|(1 << CS10);
TIMSK1 |= (1 << OCIE1A); // enable timer compare interrupt
interrupts(); // enable all interrupts
delay(500);
}
// if after OCR1A seconds no pulse from flow meter occured an interrupt will force a very high delta value
ISR(TIMER1_COMPA_vect) { // interupt service routine which will be called when an interrupt occurs at timer1
deltas[n] = UINT_MAX; // add maximum value in the current array position
n++;
if (n==N) n=0; // wrap around
}
void loop()
{
if (!setup_ok) return;
delay((int) (DISPLAY_INTERVAL*1000));
total = 0;
// sum up all deltas in array
for (int k=0; k<N; k++){
// timeout occured, break out of loop
if (deltas[k] == UINT_MAX) {
total = ULONG_MAX; // and set total to highest possible value
break;
}
total += deltas[k];
}
// calculate average flow
flow = N/(float)total/conversion*16e6/prescaler;
// flow
//flow = total/N/conversion;
// format decimal value and save string in buff
dtostrf(flow,5,3,buff);
/*
Security logic
==============
If flow is too small,i.e. flow < flow_threshold:
a) alarm LED on
b) interlock LOW
*/
if (flow < flow_threshold) {
digitalWrite(ALARM_LED_PIN, HIGH);
digitalWrite(INTERLOCK_PIN, LOW);
snprintf(serialbuff, sizeof(serialbuff), "ERR %s l/min",buff );
}
else {
digitalWrite(ALARM_LED_PIN, LOW);
digitalWrite(INTERLOCK_PIN, HIGH);
snprintf(serialbuff, sizeof(serialbuff), "OK %s l/min",buff );
}
Serial.println(serialbuff); // transmit flow
lcd.home();
lcd.print (serialbuff); // display flow
lcd.setCursor (0,1); // char 0 on line 0 or 1
//delay(DISPLAY_INTERVAL*1000);
dtostrf(flow_threshold,5,3,buff);
snprintf(serialbuff, sizeof(serialbuff), "THR %s l/min",buff );
lcd.print(serialbuff); // display threshold
}
void get_time() {
deltas[n] = TCNT1; // save current timer1 count
n++;
if (n==N) n=0; // wrap around
TCNT1 = 0; // reset timer1 counter
}