Firmware v3

.gitignore

@@ -71,9 +71,11 @@ software/FlowMeasurement/*.png
 firmware/.settings/*.prefs
 firmware/.project
 firmware/Debug/*
+firmware/Debug*
 firmware/Release/*
 *.launch
 
 # EmBitz
 *.ebTemp
 
+*.fail

.gitmodules

@@ -8,3 +8,6 @@
 [submodule "Kicad-Wago-733"]
 	path = Kicad-Wago-733
 	url = https://github.com/phd0/Kicad-Wago-733.git
+[submodule "simulations/PyLTSpice"]
+	path = simulations/PyLTSpice
+	url = https://github.com/nunobrum/PyLTSpice.git

README.md

@@ -1,3 +1,4 @@
+[![Upload to - AISLER](https://img.shields.io/badge/Upload_to_-AISLER-ff8000)](https://aisler.net/p/new?url=https://github.com/JochiSt/OpenFlowMeter/blob/main/OpenFlowMeter.kicad_pcb&ref=github)
 # OpenFlowMeter
 ## Purpose
 Measuring flow of gases and maybe liquids. 

firmware/Inc/config.h

@@ -6,14 +6,15 @@ extern "C" {
 #endif
 
 #include <stdint.h>
-
+#include "pcb_version.h"
 #include "pid.h"
 
 #define ISATURATION_LSB   3970
 #define USATURATION_LSB   3970
 
 extern const float LSB2U;
 extern const float LSB2I;
+extern const float U2I;
 
 typedef struct {
     float Ugain;
@@ -83,10 +84,19 @@ typedef struct {
      *  only the high gain is stored here, the lower gain is always 1
      *  @{
      */
+#if defined(PCB_V2)
     gain_config_t GAIN[2];
+#endif
 
     /** @}*/
 
+#if defined(PCB_V3)
+    float U_R1[2];
+    float U_R2[2];
+    float I_R1[2];
+    float I_R2[2];
+#endif
+
     /** @}*/
 } config_t;
 

firmware/Inc/pcb_version.h

@@ -0,0 +1,30 @@
+#pragma once
+
+/**
+ * PCB v1 compatibility mode
+ */
+//#define PCB_V1
+/******************************************************************************/
+/**
+ * PCB v2 compatibility mode
+ * enables:
+ *  - dual gain ADC readout
+ *  - I2C sensor readout
+ */
+//#define PCB_V2
+#if defined(PCB_V2)
+#undef PCB_V1
+#endif
+/******************************************************************************/
+/**
+ * PCB v3 compatibility mode
+ * enables:
+ *  - dual gain ADC readout
+ *  - offset for ADC / differential amplifier
+ *  - I2C sensor readout
+ */
+//#define PCB_V3
+#if defined(PCB_V3)
+#undef PCB_V1
+#undef PCB_V2
+#endif

firmware/Inc/utils.h

@@ -25,5 +25,6 @@ uint8_t upper(uint16_t val);
 uint8_t lower(uint16_t val);
 
 float convertPT100_R2T(float resistance);
+float getVoltageBeforeAmplifier(float Uadc, float Ubias, float R1, float R2);
 
 #endif //__UTILS_H__

firmware/Src/config.c

@@ -10,6 +10,8 @@ config_t cfg;
 const float LSB2U = 3.3 / 4096;
 const float LSB2I = 3.3 / 4096 * 10e-3;
 
+const float U2I = 10e-3;  // TODO insert right value here
+
 void generateDefaultCFG(config_t *cfg){
   // set the board ID
   cfg->board_ID = 1;
@@ -39,6 +41,7 @@ void generateDefaultCFG(config_t *cfg){
   cfg->PID_flags.PID0_active = 0;
   cfg->PID_flags.PID1_active = 0;
 
+#if defined(PCB_V2)
   // gain settings from calculations / optimisation
   cfg->GAIN[0].Igain = 1 + 47.0e3 / 5.6e3;
   cfg->GAIN[0].Ugain = 1 + 33.0e3 / 5.6e3;
@@ -49,6 +52,16 @@ void generateDefaultCFG(config_t *cfg){
   cfg->GAIN[1].Ugain = 1 + 33.0e3 / 5.6e3;
   cfg->GAIN[1].Ibias = 0.12;
   cfg->GAIN[1].Ubias = 0.01;
+#endif
+#if defined(PCB_V3)
+  for(int i=0; i<2; i++){
+    cfg->U_R1[i] = 47e3;
+    cfg->U_R2[i] = 5.6e3;
+    cfg->I_R1[i] = 47e3;
+    cfg->I_R2[i] = 5.6e3;
+  }
+#endif
+
 }
 
 /**
@@ -69,13 +82,23 @@ void printCfg(config_t *cfg){
   printf("SMOO:    %d\r\n", cfg->SMOO);
   printf("SMOOMAX: %d\r\n", cfg->SMOO_MAX);
 
+#if defined(PCB_V2)
   printf("\r\n");
-  printf("Gain:");
+  printf("Gain:\r\n");
   printf("  CH0 I %f U%f\r\n", cfg->GAIN[0].Igain, cfg->GAIN[0].Ugain);
   printf("  CH1 I %f U%f\r\n", cfg->GAIN[1].Igain, cfg->GAIN[1].Ugain);
-  printf("Offset:");
+  printf("Offset:\r\n");
   printf("  CH0 I %f U%f\r\n", cfg->GAIN[0].Ibias, cfg->GAIN[0].Ubias);
   printf("  CH1 I %f U%f\r\n", cfg->GAIN[1].Ibias, cfg->GAIN[1].Ubias);
+#endif
+#if defined(PCB_V3)
+  printf("\r\n");
+  printf("Resistors:\r\n");
+  for(int i=0; i<2; i++){
+    printf("  U R1 %f R2 %f\r\n", cfg->U_R1[i], cfg->U_R2[i]);
+    printf("  I R1 %f R2 %f\r\n", cfg->I_R1[i], cfg->I_R2[i]);
+  }
+#endif
 
   printf("\r\n");
   printf("PID 0: (%d)\r\n", cfg->PID_flags.PID0_active);

firmware/Src/main.c

@@ -30,6 +30,7 @@
 
 /* Private includes ----------------------------------------------------------*/
 /* USER CODE BEGIN Includes */
+#include "pcb_version.h"
 #include "syscalls.h"
 #include "utils.h"
 #include "i2c_scanner.h"
@@ -57,34 +58,7 @@
 //#define PRINT_UART_ADC        // print the ADC data
 //#define PRINT_UART_CALC_TEMP  // print the calculated temperatures
 /******************************************************************************/
-/**
- * PCB v1 compatibility mode
- */
-#define PCB_V1
-/******************************************************************************/
-/**
- * PCB v2 compatibility mode
- * enables:
- *  - dual gain ADC readout
- *  - I2C sensor readout
- */
-//#define PCB_V2
-#if defined(PCB_V2)
-#undef PCB_V1
-#define I2C_SENSOR_READOUT
-#endif
-/******************************************************************************/
-/**
- * PCB v3 compatibility mode
- * enables:
- *  - dual gain ADC readout
- *  - offset for ADC / differential amplifier
- *  - I2C sensor readout
- */
-//#define PCB_V3
-#if defined(PCB_V3)
-#undef PCB_V1
-#undef PCB_V2
+#if defined(PCB_V2) || defined(PCB_V3)
 #define I2C_SENSOR_READOUT
 #endif
 /******************************************************************************/
@@ -399,8 +373,17 @@ int main(void)
 
         // calculate coarse current and voltage for each channel
         for(int i=0; i<2; i++){
+#if defined(PCB_V1)
+          current[i] = (*avr_current[i][0] * LSB2I);
+          voltage[i] = (*avr_voltage[i][0] * LSB2U);
+#elif defined(PCB_V2)
           current[i] = (*avr_current[i][0] * LSB2I) + cfg.GAIN[i].Ibias/1000.;
           voltage[i] = (*avr_voltage[i][0] * LSB2U) + cfg.GAIN[i].Ubias;
+#elif defined(PCB_V3)
+          // TODO implement proper voltage / current reading
+          current[i] = (*avr_current[i][0] * LSB2I);
+          voltage[i] = (*avr_voltage[i][0] * LSB2U);
+#endif
         }
 
 #if defined(PCB_V2)
@@ -436,10 +419,22 @@ int main(void)
           offset[i] = 3.3 * (*PWMoffset[i]) / 4096;
         }
 
-        // adjust the offset voltage
-
-        // if offset voltage is fine, we can use the high gain
-
+        for(int i=0; i<2; i++){
+          // check for saturation
+          if(*avr_voltage[i][1] >= USATURATION_LSB || *avr_current[i][1] >= ISATURATION_LSB){
+            // one of the high gain measurement is in saturation
+            // adjust the offset voltage
+            *PWMoffset[i] += 10;
+            continue;
+          }else if(*avr_voltage[i][1] == 0 || *avr_current[i][1] == 0){
+            *PWMoffset[i] += 10;
+            continue;
+          }else{
+            // if offset voltage is fine, we can use the high gain
+            voltage[i] = getVoltageBeforeAmplifier(*avr_voltage[i][1] * LSB2U, offset[i], cfg.U_R1[i], cfg.U_R2[i]);
+            current[i] = getVoltageBeforeAmplifier(*avr_current[i][1] * LSB2U, offset[i], cfg.I_R1[i], cfg.I_R2[i]) * U2I;
+          }
+        }
 #endif
         /** calculate temperatures ********************************************/
         for(int i=0; i<2; i++){
@@ -449,23 +444,24 @@ int main(void)
         /** run the PID controllers *******************************************/
         for(int i=0; i<2; i++){
           runPID(&pid[i]);
-
           /** update the output, if the PID is active *************************/
           if(pid[0].active){
             *PWMcurrent[i] = PIDout[i];
           }else{
             *PWMcurrent[i] = PWM[i];
           }
+          /** update the offset ***********************************************/
+          *PWMoffset[i] = 0.9 * (*PWMcurrent[i]);
         }
 
-        // link the PID active to the configuration active
+        /** link the PID active to the configuration active *******************/
         pid[0].active = cfg.PID_flags.PID0_active;
         pid[1].active = cfg.PID_flags.PID1_active;
     }
 
-    /*************************************************************************
+    /***************************************************************************
      * Print some variables via UART
-     ************************************************************************/
+     **************************************************************************/
     if( cnt_print_uart >= cfg.interval_PRINT_UART
         && cfg.interval_PRINT_UART < 255
         ){

firmware/Src/utils.c

@@ -19,3 +19,14 @@ float convertPT100_R2T(float resistance){
     const float R0 = 100;
     return (resistance - R0)/(R0 * A);
 }
+
+/**
+ * calculate the voltage before the biases amplifier
+ * @param Ubias bias voltage
+ * @param Uadc measured voltage of the ADC (amplifier output)
+ * @param R1 gain setting resistor (upper)
+ * @param R2 gain setting resistor (lower)
+ */
+float getVoltageBeforeAmplifier(float Uadc, float Ubias, float R1, float R2){
+  return (R1 * Ubias + R2 * Uadc)/(R1 + R2);
+}

firmware/calculations/offset_amplifier.py

@@ -0,0 +1,28 @@
+# -*- coding: utf-8 -*-
+"""
+
+"""
+from sympy import Symbol, symbols, solve, pprint, Eq
+
+Up, Un = symbols("U_+, U_-")
+
+
+Uadc  = Symbol("U_adc")
+Ubias = Symbol("U_bias")
+
+R1, R2 = symbols("R_1, R_2")
+
+I_R1R2 = (Uadc - Ubias) / (R1 + R2)
+
+Un = I_R1R2 * R2 + Ubias
+
+eq1 = Eq( Up , Un )
+pprint(eq1)
+
+Uin = symbols("U_in")
+eq1 = eq1.subs(Up, Uin)
+pprint(eq1)
+
+sol = solve(eq1, Uin)[0].factor()
+pprint(sol)
+

simulations/CurrentSource/current_source_mod_v1.asc

@@ -197,7 +197,7 @@ SYMATTR Value 8
 SYMBOL res 352 912 R0
 SYMATTR InstName R19
 SYMATTR Value 8
-TEXT -768 712 Left 2 !.dc V3 0 3.3 0.1\n.param R_PT100 100
+TEXT -768 712 Left 2 ;.dc V3 0 3.3 0.1\n.param R_PT100 100
 TEXT -552 216 Left 2 ;R2 and R4 define current per input voltage
 TEXT -760 472 Left 2 ;max. 3.3V
 TEXT -384 504 Left 2 ;"protection" resistor
@@ -206,6 +206,7 @@ TEXT -80 832 Left 2 ;PT100 temperature sensor
 TEXT -760 880 Left 2 ;.tran 1\n.save V(voltage_measure) V(current_measure) I(Pt100)\n.step param R_PT100 100 150 10\n.measure Vmeas_avg avg V(voltage_measure)\n.measure Imeas_avg avg V(current_measure)\n.measure Ipt100_avg avg I(Pt100)
 TEXT -784 848 Left 3 ;Simulate current vs PT100
 TEXT -784 680 Left 3 ;Simulate current vs input voltage
+TEXT -1328 536 Left 2 !.tran 1\n.TEMP=30\n.param R_PT100 {100*(1+3.85e-3*TEMP)}
 LINE Normal 576 192 576 608 2
 LINE Normal 1376 192 576 192 2
 LINE Normal 576 608 1376 608 2

simulations/CurrentSource/simulate_current_source.py

@@ -0,0 +1,59 @@
+# -*- coding: utf-8 -*-
+"""
+
+"""
+import os
+import sys
+
+from functools import partial # import partial for tweaking callback
+import numpy as np
+
+sys.path.append("../PyLTSpice/")
+from PyLTSpice import SimCommander, LTSteps, RawRead
+
+sys.path.append("../../software/")
+sys.path.append("../../software/pyUSBtin")
+from OpenFlowMeter import PT100
+
+def processing_data(raw_filename, log_file, Uset):
+    print("Handling the simulation data of %s, log file %s" % (raw_filename, log_file))
+    LTR = RawRead(raw_filename)
+    # print all stored traces
+    #print(LTR.get_trace_names())
+
+    # print simulation properties
+    #print(LTR.get_raw_property())
+
+    current_setpoint= np.mean(LTR.get_trace("V(current_setpoint)").get_wave(0))
+
+    current_pt100   = np.mean(LTR.get_trace("I(PT100)").get_wave(0))*1000
+
+    current_measure = np.mean(LTR.get_trace("V(current_measure)").get_wave(0))
+    voltage_measure = np.mean(LTR.get_trace("V(voltage_measure)").get_wave(0))
+
+    print("I set    ", current_setpoint)
+    print("I PT100  ", current_pt100)
+    print("I measure", current_measure)
+    print("U measure", voltage_measure)
+
+    R_PT100 = voltage_measure / (current_measure * 10 / 1000)
+    print("R_PT100: ", R_PT100)
+    print("Temperature", PT100.convertPT100_T(R_PT100))
+
+
+# select spice model
+
+LTC = SimCommander(
+    "./current_source_mod_v1.asc",
+    parallel_sims=2             # limit number of parallel simulations)
+    )
+LTC.set_parameters(temp=40)
+
+for Uset in [0.5, 1, 1.5, 2, 2.5, 3, 3.3]:
+    LTC.set_component_value('V3', Uset)
+    LTC.run(callback=partial(processing_data, Uset=None))
+
+LTC.wait_completion()
+
+# Sim Statistics
+print('Successful/Total Simulations: ' + str(LTC.okSim) + '/' + str(LTC.runno))