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OperaHouse

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9 Element Heating with High Efficiency PV Solar
« on: March 02, 2018, 08:44:13 AM »
While Damon is away it is a good time to post this. Don't want him to have a heart attack.

Large PV array water heating with up to 9 heating elements for tube floor heating. This
program progressively turns on up to 9 heating elements in multiple steps to maintain
power point. Initial 20 steps are smaller to accommodate lower power light levels. This
switching in and out of elements always matches resistance to the panels power point
voltage. Eight elements are turned either on or off. The ninth element is PWMed from a
capacitor storage bank to allow power to increase in about 2% steps. HYST is adjustable
for smoother element transition. Internally set point is fixed, voltage is adjusted
with external pot. Elements 1-8 only need a slow FET driver. PWM rate is 240Hz requiring
just a slightly faster driver. This is a concept program and has not been tested in operation.
 
Code is written in a very simplistic form that a total beginner can understand and modify to your situation.
If you can't understand and maintain this code you  should avoid this project. It's a demonstrator  for beginners.

D12 = Heat Switch, close to common for heat
A0  = PV voltage, about 2.8V from voltage divider
A1  = HYST voltage change needed to transition, connect to 3V3 if pot not used

D3  = Element #9 PWM element must always be present
D2  = Element #1
D4  = Element #2 three elements total is suggested minimum system
D5  = Element #3
D7  = Element #4
D8  = Element #5
D9  = Element #6 
D10 = Element #7
D11 = Element #8


/*
   PE9 FLOOR HEAT is program for tank heating with 9 heating elements of
   the same value resistance. 8 elements are ON/OFF & one is multi step PWM.
   For use with large tank systems capable of multiple heating elements.
   Panel volts are read on A0 from a pot divider. Internal PV set point fixed.
   Uses relay contact temp sensor on D12 input to common for heat. Must use
   470 ohm pullup with LED in series to indicate heat mode is on. Hystresis
   is adjustable from A1 for step change. Analog power (step) out pin 6 for
   meter. Any number of heating elements may be used, must include PWM.
   Initial power levels are progressive.
 
 1.  Blink LED 13 ONCE periodically to show micro is working
 2.  Blink LED 13 additional multiple times for heating level
 3.  Read panel voltage eight times to get average
 4.  8 elements ON/OFF, one PWM multi step
 5.  Progressively higher steps at low power
 6.  External temp controller, switch contact
 7.  Send out serial data periodically of all variables



 
 Ver 1.1  02/17/18 semi working baseline program
 revised  02/18/18 added ninth element and progressive power levels               
 
 The following two characters * and / end a multi line comment
 */
 
// Declare program variables as integers and set initial values
                             // ALL THE SEQUENTIAL PANEL READINGS
int PV0            = 0;      // SOLAR PANEL raw A/D conversion #1
int PV1            = 0;      // SOLAR PANEL raw A/D conversion #2
int PV2            = 0;      // SOLAR PANEL raw A/D conversion #3
int PV3            = 0;      // SOLAR PANEL raw A/D conversion #4
int PV4            = 0;      // SOLAR PANEL raw A/D conversion #5
int PV5            = 0;      // SOLAR PANEL raw A/D conversion #6
int PV6            = 0;      // SOLAR PANEL raw A/D conversion #7
int PV7            = 0;      // SOLAR PANEL raw A/D conversion #8

int ADavg          = 0;      // Solar panel average A/D value
int SETpoint       = 600;    // panel power point for heating (about 2.8V)
int HYST           = 0 ;     // panel power point HYST

int COUNTheater    = 0;      // WATER HEATER UP/DOWN COUNTER
int PWM3drv        = 0;      // WATER HEATER PWM ELEMENT driver

int ELEMENT_1      = 0;      // #1 WATER HEATER ELEMENT ON/OFF state
int ELEMENT_2      = 0;      // #2 WATER HEATER ELEMENT ON/OFF state
int ELEMENT_3      = 0;      // #3 WATER HEATER ELEMENT ON/OFF state
int ELEMENT_4      = 0;      // #4 WATER HEATER ELEMENT ON/OFF state
int ELEMENT_5      = 0;      // #5 WATER HEATER ELEMENT ON/OFF state
int ELEMENT_6      = 0;      // #6 WATER HEATER ELEMENT ON/OFF state
int ELEMENT_7      = 0;      // #7 WATER HEATER ELEMENT ON/OFF state
int ELEMENT_8      = 0;      // #8 WATER HEATER ELEMENT ON/OFF state

int blinktime      = 0;      // Used to blink LED power level
int PRINTcycle     = 0;      // used for periodic serial print


  void setup() {               
  // initialize the digital pins as outputs.
  // Pin 13 is on board LED and is a visual
  // indicator the micro is working

  pinMode(13, OUTPUT);        // Onboard Monitor LED
  pinMode(12, INPUT);         // TEMP switch contact 0=heat
  pinMode(11, OUTPUT);        // ELEMENT #8
  pinMode(10, OUTPUT);        // ELEMENT #7
  pinMode(9, OUTPUT);         // ELEMENT #6
  pinMode(8, OUTPUT);         // ELEMENT #5
  pinMode(7, OUTPUT);         // ELEMENT #4
  pinMode(5, OUTPUT);         // ELEMENT #3
  pinMode(4, OUTPUT);         // ELEMENT #2
  pinMode(2, OUTPUT);         // ELEMENT #1
  pinMode(6, OUTPUT);         // 960Hz  PWM METER OUT (reference only)
  pinMode(3, OUTPUT);         // 244Hz  PWM ELEMENT #9 (reference only)
 
 
  digitalWrite (12,1);        // set weak pullup on D12 (old version)
  Serial.begin (9600);        // Set up serial monitor routine, 9600 baud
}                             // End setup

void loop() {                 // This is the start of the program loop
   
    //  *****************************************************************
    //  LOWER THE PWM FREQUENCY FOR LESS FET HEATING and SIMPLE DRIVER
   
    // This changes the frequency of PWM pins 11 & 3 ONLY
    // Fewer transitions = less heat created
    // Pins 11 and 3 for 16MHz clock
    // Settinng     Divisor    Hz
    // 0x01         1         31250
    // 0x02         8       3906
    // 0x03         32      976
    // 0x04         64      488
    // 0x05         128     244
    // 0x06         256     122
    // 0x07         1024    30
   
    // TCCR2B = TCCR2B & 0b11111000 | <setting>;
   
    TCCR2B = TCCR2B & 0b11111000 | 0x05;   // changes the PWM rate 11 & 3
   
    // PWM pins 9 & 10  These you can change as above
    // TCCR1B = TCCR1B & 0b11111000 | <setting>;
   
    //TCCR1B = TCCR1B & 0b11111000 | 0x06 ;
   
    //Pins 5 and 6: Standard
    // changing this changes program delay times  AVOID
    //Setting    Divisor   Frequency
    // 0x03       64          976
    //TCCR0B = TCCR0B & 0b11111000 | 0x03 ;
   
  //  *********************************************************
  // This section reads the analog signals.  Range is 0 to 5V DC or 0 to 1023
  // counts. A delay before the first read allows capacitor bank voltage to
  // stabilize fron new PWM.  Eight readings average out noise which can
  // be several counts. We don't have much to do and lots of time so might as well.
 
 
  HYST = analogRead (1);           // Anolog In.  HYST voltage from pot on A1
  HYST = HYST / 50 + 8;            // HYST from 8 to 28
                                   // NOTE: Tie A1 to 3V3 if pot not used
 
  delay (200);                     // Delay before first reading allowing last
                                   // PWM to take effect on capacitor bank
                                                       
  PV0  = analogRead (0);           // Anolog In.  Read the panel voltage  #1
  delay (4);                       // Delay between readings
  PV1  = analogRead (0);           // Anolog In.  Read the panel voltage  #2
  delay (4);                       // Delay between readings
  PV2  = analogRead (0);           // Anolog In.  Read the panel voltage  #3
  delay (4);                       // Delay between readings
  PV3  = analogRead (0);           // Anolog In.  Read the panel voltage  #4
  delay (4);                       // Delay between readings
  PV4  = analogRead (0);           // Anolog In.  Read the panel voltage  #5
  delay (4);                       // Delay between readings
  PV5  = analogRead (0);           // Anolog In.  Read the panel voltage  #6
  delay (4);                       // Delay between readings
  PV6  = analogRead (0);           // Anolog In.  Read the panel voltage  #7
  delay (4);                       // Delay between readings
  PV7  = analogRead (0);           // Anolog In.  Read the panel voltage  #8
  delay (4);
 
  // ###################################################
  // This section gets the average of the eight readings to remove noise which
  // can be several counts. Simplified to be unserstood by new programmers.
  // Average should closely match raw A/D values.
 
  ADavg = PV0 + PV1 + PV2 + PV3 + PV4 + PV5 + PV6 + PV7;  // Add the eight readings
  ADavg = ADavg / 8;                                      // get average reading
 
                                                               
 
  // ########################################################
  //                             HEATER CONTROL
  // This section controls the up/down count for the 9 heaters shown. Minimum of three
  // heaters should be connected. It will operate fine with additional heaters up to
  // 9. Once written to, the PWM stays at that duty cycle till changed. When PWM count
  // reaches 5 (typical)the next heater is turned on and PWM drive goes to zero.
  // This allows minimal size capacitor bank.
 
  // Up / DOWN counter of heater
  // Increasing duty cycle
  if (ADavg > SETpoint)  COUNTheater = COUNTheater + 1;             // Is panel voltage higher than
                                                                    // power point, add fine tune UP
 
  // Decreasing duty cycle
  if (ADavg < SETpoint - HYST )  COUNTheater = COUNTheater - 1;     // panel voltage lower than power
                                                                    // point, subtract fine tune DOWN 
  // Big step down for big A/D change (sudden cloud)
  if (ADavg > SETpoint - HYST - 25) COUNTheater = COUNTheater - 3;  // panel voltage much lower, subtract 
                                                                    // RAPID response for big change DOWN
                                                                     
  //*******************************************************************                                                               
  // COUNTheater = analogRead (7);          // TEST TEST TEST  manually enter count ******
  // COUNTheater = COUNTheater / 18;        // TEST TEST TEST  with pot, up to 56 *******
  //********************************************************************
 
 
  // Check switched temp input D12 to see if HEAT REQUESTED
  // Weak pullup, add external LED & 470 ohm resistor for sufficient contact current
 
  if (digitalRead(12) == 1) COUNTheater = 0;         // TEMP SWITCH OPEN, HEAT not requested       
                                                     // turn off all drive to elements
  // place limits on count
  if (COUNTheater <= 0) COUNTheater = 0;             // Limit Lower boundry of COUNT to zero
  if (COUNTheater >= 56) COUNTheater = 56;           // Limit upper boundry of COUNT
                                                     // 56 indicates not enough load, maxed out
 
  // #################################################################
  // FIRST ELEMENT     FIRST ELEMENT     FIRST ELEMENT      FIRST ELEMENT      FIRST ELEMENT     
 
  if (COUNTheater >= 13) ELEMENT_1 = 1;               // turn ELEMENT_1 ON 
  if (COUNTheater < 13)  ELEMENT_1 = 0;               // turn ELEMENT_1 OFF
 
  digitalWrite (2, ELEMENT_1);                        // output state of ELEMENT_1

  // ###################################################################
  // SECOND ELEMENT     SECOND ELEMENT   SECOND ELEMENT    SECOND ELEMENT   SECOND ELEMENT   
 
  if (COUNTheater >= 20) ELEMENT_2 = 1;               // turn ELEMENT_2 ON 
  if (COUNTheater < 20)  ELEMENT_2 = 0;               // turn ELEMENT_2 OFF
 
  digitalWrite (4, ELEMENT_2);                        // output state of ELEMENT_2

  // #################################################################
  // THIRD ELEMENT     THIRD ELEMENT     THIRD ELEMENT     THIRD ELEMENT    THIRD ELEMENT   
 
  if (COUNTheater >= 25) ELEMENT_3 = 1;               // turn ELEMENT_3 ON 
  if (COUNTheater < 25)  ELEMENT_3 = 0;               // turn ELEMENT_3 OFF
 
  digitalWrite (5, ELEMENT_3);                        // output state of ELEMENT_3
 
  // #####################################################################
  // FOURTH ELEMENT     FOURTH ELEMENT     FOURTH ELEMENT     FOURTH ELEMENT    FOURTH  ELEMENT
 
  if (COUNTheater >= 30) ELEMENT_4 = 1;               // turn ELEMENT_4 ON 
  if (COUNTheater < 30)  ELEMENT_4 = 0;               // turn ELEMENT_4 OFF
 
  digitalWrite (7, ELEMENT_4);                        // output state of ELEMENT_4

  // ###############################################################
  //  FIFTH ELEMENT     FIFTH ELEMENT     FIFTH ELEMENT     FIFTH ELEMENT    FIFTH  ELEMENT
 
  if (COUNTheater >= 35) ELEMENT_5 = 1;               // turn ELEMENT_5 ON 
  if (COUNTheater < 35)  ELEMENT_5 = 0;               // turn ELEMENT_5 OFF
 
  digitalWrite (8, ELEMENT_5);                        // output state of ELEMENT_5
 
  // ################################################################
  //  SIXTH ELEMENT     SIXTH ELEMENT     SIXTH ELEMENT     SIXTH ELEMENT    SIXTH  ELEMENT
 
  if (COUNTheater >= 40) ELEMENT_6 = 1;               // turn ELEMENT_6 ON 
  if (COUNTheater < 40)  ELEMENT_6 = 0;               // turn ELEMENT_6 OFF
 
  digitalWrite (9, ELEMENT_6);                        // output state of ELEMENT_5
 
  // ######################################################################
  //  SEVENTH ELEMENT   SEVENTH ELEMENT   SEVENTH ELEMENT    SEVENTH ELEMENT   SEVENTH  ELEMENT
 
  if (COUNTheater >= 45) ELEMENT_7 = 1;               // turn ELEMENT_7 ON 
  if (COUNTheater < 45)  ELEMENT_7 = 0;               // turn ELEMENT_7 OFF
 
  digitalWrite (10, ELEMENT_7);                       // output state of ELEMENT_7
 
  // ####################################################################
  //  EIGHTH ELEMENT     EIGHTH ELEMENT    EIGHTH ELEMENT    EIGHTH ELEMENT    EIGHTH  ELEMENT
 
  if (COUNTheater >= 50) ELEMENT_8 = 1;               // turn ELEMENT_8 ON 
  if (COUNTheater < 50)  ELEMENT_8 = 0;               // turn ELEMENT_8 OFF
 
  digitalWrite (11, ELEMENT_8);                       // output state of ELEMENT_8
 
 
  // #################################################################
  // PWM LAST ELEMENT      PWM LAST ELEMENT      PWM LAST ELEMENT      PWM LAST ELEMENT   
  // If elements are not the same resistanve, use the lowest resistance for PWM element
  // clunky, but easy to understand. Initialize PWM drive to zero each loop for default
 
  PWM3drv = 0;                                       
 
  // NOW SET PWM VALUE
  // LOWEST RANGE smaller progressive steps, avoid short time on first count
  if (COUNTheater == 1)  PWM3drv = 9;                 // turn LAST ELEMENT 4% ON
  if (COUNTheater == 2)  PWM3drv = 15;                // turn LAST ELEMENT 6% ON 
  if (COUNTheater == 3)  PWM3drv = 25;                // turn LAST ELEMENT 10% ON   
  if (COUNTheater == 4)  PWM3drv = 35;                // turn LAST ELEMENT 14% ON
  if (COUNTheater == 5)  PWM3drv = 50;                // turn LAST ELEMENT 20% ON 
  if (COUNTheater == 6)  PWM3drv = 75;                // turn LAST ELEMENT 30% ON 
  if (COUNTheater == 7)  PWM3drv = 100;               // turn LAST ELEMENT 40% ON   
  if (COUNTheater == 8)  PWM3drv = 125;               // turn LAST ELEMENT 50% ON
  if (COUNTheater == 9)  PWM3drv = 150;               // turn LAST ELEMENT 58% ON
  if (COUNTheater == 10)  PWM3drv = 175;              // turn LAST ELEMENT 68% ON 
  if (COUNTheater == 11)  PWM3drv = 200;              // turn LAST ELEMENT 78% ON 
  if (COUNTheater == 12)  PWM3drv = 225;              // turn LAST ELEMENT 88% ON   
  // HEATER #1 TURNS ON AT 13
   
  // larger progressive steps
  if (COUNTheater == 14)  PWM3drv = 30;               // turn LAST ELEMENT 12% ON 
  if (COUNTheater == 15)  PWM3drv = 65;               // turn LAST ELEMENT 25% ON 
  if (COUNTheater == 16)  PWM3drv = 100;              // turn LAST ELEMENT 39% ON   
  if (COUNTheater == 17)  PWM3drv = 135;              // turn LAST ELEMENT 53% ON
  if (COUNTheater == 18)  PWM3drv = 170;              // turn LAST ELEMENT 67% ON 
  if (COUNTheater == 19)  PWM3drv = 210;              // turn LAST ELEMENT 82% ON   
  // HEATER #2 TURNS ON AT 20
 
 
  // Begin 5 step at this power level
  if (COUNTheater == 21) PWM3drv = 50;                // turn LAST ELEMENT 1/5 ON 
  if (COUNTheater == 22) PWM3drv = 100;               // turn LAST ELEMENT 2/5 ON 
  if (COUNTheater == 23) PWM3drv = 150;               // turn LAST ELEMENT 3/5 ON   
  if (COUNTheater == 24) PWM3drv = 200;               // turn LAST ELEMENT 4/5 ON 
  // HEATER #3 TURNS ON AT 25
 
  if (COUNTheater == 26) PWM3drv = 50;                // turn LAST ELEMENT 1/5 ON 
  if (COUNTheater == 27) PWM3drv = 100;               // turn LAST ELEMENT 2/5 ON 
  if (COUNTheater == 28) PWM3drv = 150;               // turn LAST ELEMENT 3/5 ON   
  if (COUNTheater == 29) PWM3drv = 200;               // turn LAST ELEMENT 4/5 ON   
  // HEATER #4 TURNS ON AT 30
 
  if (COUNTheater == 31) PWM3drv = 50;                // turn LAST ELEMENT 1/5 ON 
  if (COUNTheater == 32) PWM3drv = 100;               // turn LAST ELEMENT 2/5 ON 
  if (COUNTheater == 33) PWM3drv = 150;               // turn LAST ELEMENT 3/5 ON   
  if (COUNTheater == 34) PWM3drv = 200;               // turn LAST ELEMENT 4/5 ON   
  // HEATER #5 TURNS ON AT 35
 
  if (COUNTheater == 36) PWM3drv = 50;                // turn LAST ELEMENT 1/5 ON 
  if (COUNTheater == 37) PWM3drv = 100;               // turn LAST ELEMENT 2/5 ON 
  if (COUNTheater == 38) PWM3drv = 150;               // turn LAST ELEMENT 3/5 ON   
  if (COUNTheater == 39) PWM3drv = 200;               // turn LAST ELEMENT 4/5 ON   
  // HEATER #6 TURNS ON AT 40
 
  if (COUNTheater == 41) PWM3drv = 50;                // turn LAST ELEMENT 1/5 ON 
  if (COUNTheater == 42) PWM3drv = 100;               // turn LAST ELEMENT 2/5 ON 
  if (COUNTheater == 43) PWM3drv = 150;               // turn LAST ELEMENT 3/5 ON   
  if (COUNTheater == 44) PWM3drv = 200;               // turn LAST ELEMENT 4/5 ON   
  // HEATER #7 TURNS ON AT 45
   
  if (COUNTheater == 46) PWM3drv = 50;                // turn LAST ELEMENT 1/5 ON 
  if (COUNTheater == 47) PWM3drv = 100;               // turn LAST ELEMENT 2/5 ON 
  if (COUNTheater == 48) PWM3drv = 150;               // turn LAST ELEMENT 3/5 ON   
  if (COUNTheater == 49) PWM3drv = 200;               // turn LAST ELEMENT 4/5 ON 
  // HEATER #8 TURNS ON AT 50
 
  //HIGHEST POWER RANGE
  if (COUNTheater == 51) PWM3drv = 50;                // turn LAST ELEMENT 1/5 ON 
  if (COUNTheater == 52) PWM3drv = 100;               // turn LAST ELEMENT 2/5 ON 
  if (COUNTheater == 53) PWM3drv = 150;               // turn LAST ELEMENT 3/5 ON   
  if (COUNTheater == 54) PWM3drv = 200;               // turn LAST ELEMENT 4/5 ON 
  if (COUNTheater >= 55) PWM3drv = 255;               // turn LAST ELEMENT FULLY ON   
 
  digitalWrite (3,PWM3drv);                           // output state of PWM ELEMENT
                                         
  // *************************************************************************                                   
  // Analog Power output signal for external power meter 0-100% (ACTUALLY STEPS) if used
 
  analogWrite(6, COUNTheater * 9 / 2);    // analogWrite 0 to 255 to D6 POWER LEVEL METER
                                          // each count is 255/57 or approximately 4.5

  // ##################################################################
  // This section blinks the on board LED #13

  blinktime = blinktime + 1;                        // increment blink timer each loop
 
  if (blinktime >= 100) blinktime = 0;              // 100 loops per blink cycle, reset
 
  // This section blinks LED ONCE to show program is operating

  if (blinktime == 1)  digitalWrite (13, LOW);      // LED OFF INSURE INITIAL INDICATOR OFF

  if (blinktime == 3) digitalWrite (13, HIGH);      // LED ON   ONE BLINK CPU RUNNING
  if (blinktime == 15) digitalWrite (13, LOW);      // turn LED OFF

  // This section blinks LED to show power level, STATUS LED #13
  if (blinktime == 20 && COUNTheater >= 10) digitalWrite( 13, HIGH);  // LED ON Second BLINK low
  if (blinktime == 25) digitalWrite (13, LOW);                        // turn LED OFF

  if (blinktime == 30 && COUNTheater >= 18) digitalWrite (13, HIGH);  // LED ON  Third BLINK 
  if (blinktime == 32) digitalWrite (13, LOW);                        // turn LED OFF

  if (blinktime == 34 && COUNTheater >= 25) digitalWrite (13, HIGH);  // LED ON  Fourth BLINK   
  if (blinktime == 36) digitalWrite (13, LOW);                        // turn LED OFF

  if (blinktime == 38 && COUNTheater >= 32) digitalWrite (13, HIGH);  // LED ON  Fifth BLINK 
  if (blinktime == 40) digitalWrite (13, LOW);                        // turn LED OFF

  if (blinktime == 42 && COUNTheater >= 39) digitalWrite (13, HIGH);  // LED ON  Sixth BLINK 
  if (blinktime == 44) digitalWrite (13, LOW);                        // turn LED OFF

  if (blinktime == 46 && COUNTheater >= 46) digitalWrite (13, HIGH);  // LED ON  Seventh BLINK
  if (blinktime == 48) digitalWrite (13, LOW);                        // turn LED OFF
 
  if (blinktime == 50 && COUNTheater >= 53) digitalWrite (13, HIGH);  // LED ON  Eighth BLINK   
  if (blinktime == 52) digitalWrite (13, LOW);                        // turn LED OFF

 
  // ###############################################################
 
  // This section prints the values to the programmers serial screen.  Printing takes time. It
  // is done after a number of program loops and the count is reset. This speeds up the loop
  // and makes reading data easier
 
  PRINTcycle = PRINTcycle + 1;        // increment printer count
 
  if (PRINTcycle >= 10)               // if count reached, do the following between brackets
  {                                   // start of stuff to do
  PRINTcycle = 0;                     // reset counter value
 
  // print four spaced A/D readings. This can indicate capacitor bank droop
  Serial.print(PV0);                  // raw PV value #0
  Serial.print("  ");
  Serial.print(PV2);                  // raw PV value #2
  Serial.print("  ");
  Serial.print(PV4);                  // raw PV value #4
  Serial.print("  ");
  Serial.print(PV6);                  // raw PV value #6
  Serial.print(" raw  ");                 
 
  Serial.print(ADavg);                // averaged A/D value of the EIGHT readings
  Serial.print(" avg   ");
 
  Serial.print(HYST);                 // differential count between steps
  Serial.print("H   ");
   
  Serial.print(COUNTheater);          // output overall heater count value
  Serial.print(" cnt   ");
 
  Serial.print(ELEMENT_1);            // following ON/OFF states of each heater       
  Serial.print("  ");
 
  Serial.print(ELEMENT_2);                   
  Serial.print("  ");
 
  Serial.print(ELEMENT_3);                   
  Serial.print("  ");
 
  Serial.print(ELEMENT_4);                   
  Serial.print("  ");
 
  Serial.print(ELEMENT_5);                   
  Serial.print("  ");
 
  Serial.print(ELEMENT_6);                 
  Serial.print("  ");   
 
  Serial.print(ELEMENT_7);                 
  Serial.print("  "); 

  Serial.print(ELEMENT_8);                 
  Serial.print("    "); 
 
  Serial.print(PWM3drv);               // output PWM value for LAST heater
  Serial.println(" PWM3  V1.1");       // This is like the carrage return if
                                       // you know what a typwriter is
                                         
  }                                    // end bracket, print routine
                                       // this is end of all printing stuff
   
  // ##############################################################
     
} // END of the program loop

« Last Edit: March 02, 2018, 08:52:12 AM by OperaHouse »
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ontfarmer

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Re: 9 Element Heating with High Efficiency PV Solar
« Reply #1 on: March 03, 2018, 05:49:55 AM »
Thanks  OperaHouse for  posting.
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Bruce S

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Re: 9 Element Heating with High Efficiency PV Solar
« Reply #2 on: March 05, 2018, 08:55:46 AM »
OperaHouse;
I forgot to mention/ask, is it my FireFox or did the auto-correct change step 8 to a emoji 8)?
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joestue

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Re: 9 Element Heating with High Efficiency PV Solar
« Reply #3 on: March 05, 2018, 02:06:15 PM »
Any reason not to do the 8,4,2,1 ratio of wattage on the heating elements and switch them out in binary?
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OperaHouse

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Re: 9 Element Heating with High Efficiency PV Solar
« Reply #4 on: March 05, 2018, 03:54:22 PM »
Spoken like an engineer. Because real life doesn't operate in binary. People buy nine identical heater elements.  Had this argument with Dacian.  Ok if you are burying heater wire in concrete with different lengths.  Practically, it just doesn't work out.


I don't see it. Personally, I hope there is a little zinger in each program so they have to work at least something out. Otherwise I would have just given them a file. Not much into R&C.
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joestue

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Re: 9 Element Heating with High Efficiency PV Solar
« Reply #5 on: March 05, 2018, 06:38:04 PM »
Quote from: OperaHouse on March 05, 2018, 03:54:22 PM
Practically, it just doesn't work out.

true, to some extent. with water heater elements you do have a wide range to choose from but they won't be an exact fit, will still need pwm on one or more of them.
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SparWeb

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Re: 9 Element Heating with High Efficiency PV Solar
« Reply #6 on: March 06, 2018, 08:48:44 PM »
Bruce,
This program is about heaters.  It is not THAT cool  8)

OH,
I was recently working on a schematic using a LT1154 FET gate driver.
http://www.linear.com/product/LTC1154
Suitable for this project?
(It's a bit complicated, with current monitoring and fault protection built in... but I wouldn't know if these features are common for gate drivers or not).
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joestue

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Re: 9 Element Heating with High Efficiency PV Solar
« Reply #7 on: March 06, 2018, 09:24:58 PM »
Quote from: SparWeb on March 06, 2018, 08:48:44 PM
Suitable for this project?


4.5V to 18V Supply Range

it would work on a 12v system.

these are good for a 48v system.. theoretically. http://www.linear.com/product/LT1910 3$ each though...
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OperaHouse

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Re: 9 Element Heating with High Efficiency PV Solar
« Reply #8 on: March 07, 2018, 08:44:45 AM »
I can't see a real need for a high side FET driver in this project.  It certainly does not need a high speed driver. Those will get most people in a lot of trouble due to fast rise times.  All that is needed is a handful of PC817 opto isolators to act ah a 12V driver. I should post these little modules I make that are ideal and cheap.
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Aswanirahil

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Re: 9 Element Heating with High Efficiency PV Solar
« Reply #9 on: June 25, 2019, 12:57:28 AM »
Nice information shared.  :)
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