Revision 0:c54aeef9c92d, committed 2018-09-24

Comitter:

AlexStokoe

Date:

Mon Sep 24 09:21:06 2018 +0000

Commit message:

code for running extended time stability logging tests;

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Mon Sep 24 09:21:06 2018 +0000
@@ -0,0 +1,212 @@
+#include "mbed.h"
+
+// thermal cycling settings
+#define N_CYCLES             1     // number of thermal cycles (ramp-hold-ramp-hold)
+#define R_SETPOINT_LOW  0.9800     // heater resistance at low temp R60
+#define T_LOW_RAMP       10000     // low temperature ramp time (ms)
+#define T_LOW_HOLD         500     // low temperature hold time (ms)
+#define R_SETPOINT_HIGH    1.1     // heater resistance at high temp R95
+#define T_HIGH_RAMP      10000     // high temperaure ramp time (ms)
+#define T_HIGH_HOLD      10000     // high temperature time (ms)
+#define T_HIGH_START      0000     // hotstart time(ms)
+
+// temperature measurement settings
+#define N_SAMPLES            1     // number of samples to acquire for I and V measurements
+#define N_ROLL_AVG          10     // rolling average for R values
+#define PULSE_WIDTH       5000     // heat or cool pulse width (us)
+#define MEAS_DELAY         50     // measurement delay after turning on FET (us)
+#define CAM_TRIG            20     // camera trigger pulse width (us)
+#define LOG_INTERVAL       500     // log file interval (ms)
+
+// ADC channels to read
+#define CH_A                 1     // value of convst bus to read channel A only
+#define CH_AC                5     // value of convst bus to read channels A and C
+#define CH_ABCD             15     // value of convst bus to read all chanels simultaneously
+
+Serial pc(USBTX, USBRX); // tx, rx
+
+DigitalOut drive(p21);            // drive FET
+DigitalOut yLED(p27);             // yellow LED (drive on)
+DigitalOut gLED(p28);             // green LED (power on)
+DigitalOut rLED(p26);             // red LED (thermocycling in progress)
+DigitalOut camTrig(p24);          // trigger camera
+
+AnalogIn battVolt(p19);
+AnalogIn auxVolt(p20);
+
+BusOut convt(p11, p12, p13, p14);
+SPI spi(p5, p6, p7);              // mosi, miso, sclk
+DigitalOut cs(p8);                // chip select
+DigitalIn busy(p9);
+DigitalOut reset(p10);
+
+Timer timer;
+LocalFileSystem local("local");
+
+FILE *fp = fopen("/local/TEST_LOG.csv", "w");  // Open "test_log" on the local file system for writing
+
+float r = 0;
+float rAvg = 0;
+float rAcc = 0;
+float rSet;
+
+int nAcc = 0;
+int eTime;
+int logTime = 0;
+int iCycle = 0;
+
+char outString[100];
+
+char buffer16[16];
+int val_array[8];
+const char dummy = 0;
+
+void logFile(void) {
+    rAcc = rAcc + r;
+    nAcc++;
+    if (eTime > logTime) {
+       // trigger camera 
+       camTrig = 1;
+       wait_us(CAM_TRIG);
+       camTrig = 0;
+
+       // write data
+       sprintf(outString, "$%1.6f$\n",rAcc/nAcc); // log data
+       pc.printf("%s",outString);
+       fprintf(fp, outString);
+       logTime = logTime + LOG_INTERVAL;
+       rAcc = 0;
+       nAcc = 0;
+    }
+}
+
+void readChannels (char buffer[16], int values[8]){
+    //simultaneously samples and reads into buffer
+    short int val_array[8];
+             
+    //send convert signal to channels
+    convt = CH_AC;
+    wait_us(1);
+    convt = 0;
+                
+    //SPI(like) data transfer
+    cs = 0;
+    spi.write(&dummy, 1, buffer, 16);
+    cs=1;
+       
+    //loop over bytes to add channel voltage values
+    for (int i=0; i<8; i++){
+        val_array[i] = buffer[2*i]<<8 | buffer16[(2*i) + 1];
+        values [i] = val_array[i];   
+    }            
+    r = (double)(val_array[5]-val_array[4])/(double)(val_array[1]-val_array[0]);
+}
+    
+void tempControl(int endTime){
+    eTime = timer.read_ms();
+    while (eTime < endTime) {
+        yLED = 1;
+        drive = 1;
+        wait_us(MEAS_DELAY);                         // wait for heater current to stabilise
+        readChannels (buffer16, val_array);          // read ADC channels and update r
+        rAvg = ((N_ROLL_AVG-1)*rAvg + r)/N_ROLL_AVG; // calculate rolling average r
+        // printf("hold r: %8.4f\r\n",r);
+        if (rAvg > rSet) {
+            drive = 0; // turn off heater if setpoint resistance is exceeded  
+            yLED = 0;
+        }
+        // printf("set r: %8.4f\r\n",r);
+           
+        logFile();
+        wait_us(PULSE_WIDTH);  //wait until pulse_width (us) has elapsed  
+        eTime = timer.read_ms();
+     }    
+}
+
+void tempControlRamp(float setStartR, float setEndR, int endTime){
+    float setRate;
+    int startTime;
+    
+    startTime = timer.read_ms();
+    setRate = (setEndR - setStartR)/(endTime - startTime);
+    eTime = startTime;
+    while (eTime < endTime) {
+        rSet = setStartR + setRate*(eTime - startTime);
+        yLED = 1;
+        drive = 1;
+        wait_us(MEAS_DELAY); // wait for heater current to stabilise
+        readChannels (buffer16, val_array);          // read ADC channels and update r
+        rAvg = ((N_ROLL_AVG-1)*rAvg + r)/N_ROLL_AVG; // measure r
+        if (rAvg > rSet) {
+            drive = 0; // turn off heater if setpoint resistance is exceeded  
+            yLED = 0;
+        }
+        // printf("ramp r: %8.4f\r\n",r);
+
+        logFile();
+        wait_us(PULSE_WIDTH);  //wait until pulse_width (us) has elapsed  
+        eTime = timer.read_ms();
+    }    
+}
+
+
+int main() {
+    int endTime = 0;
+     
+    rLED = 0;
+    yLED = 0;
+    gLED = 0;
+    
+    drive = 0;
+       
+    pc.baud(115200);
+    //Reset ADC sequence
+
+    reset = 1;
+    wait_ms(1);
+    reset = 0;
+    
+    //set SPI serial to 2MHz, 16 bit data transfer, mode 2 (clock normally high, data preceeding clock cycle) 
+    spi.format(8,2);
+    spi.frequency(2000000);
+    spi.set_default_write_value(0x00);
+    cs = 1;
+
+    rLED = 1;  // thermal cycling in progress
+    yLED = 0;  // heater on
+    gLED = 1;  // microprocessor power on
+    
+    sprintf(outString,"$r$\n");  
+    pc.printf("%s", outString);
+    fprintf(fp, outString);
+  
+    timer.start();
+    
+    // optional hot start: additional HIGH temperature time at start
+    if (T_HIGH_START > 0) {
+          endTime = T_HIGH_START;
+          rSet = R_SETPOINT_HIGH;
+          tempControl(endTime);
+    }
+
+    // loop forever
+    while(1) {
+        
+        
+        // hold at HIGH temperature
+        endTime = endTime + T_HIGH_HOLD;
+        rSet = R_SETPOINT_HIGH;
+        tempControl(endTime);
+        
+        
+        
+    }        
+  
+    // extinguish rLED (thermocycling complete), ensure heater is off and close log file for access
+    drive = 0;
+    rLED = 0; 
+    logTime = 0;
+    logFile();
+    fclose(fp);     
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Mon Sep 24 09:21:06 2018 +0000
@@ -0,0 +1,1 @@
+https://os.mbed.com/users/mbed_official/code/mbed/builds/e95d10626187
\ No newline at end of file