Library containing essential automation elements with parameters in continuous Laplace domain, and implemented with fixed sample time. This means that "out" member functions should be called using Ticker object.

Dependents:   CurrentMeasurement Zavrsni_rad_NXP_cup HC-SR04 Nucleo_SSD1306_DS1302_ESP8266_AM2320_BME280 ... more

Revision:
0:3dd7aeceee65
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PI.cpp	Thu Jan 22 11:41:02 2015 +0000
@@ -0,0 +1,72 @@
+#include "PI.h"
+
+PI::PI() {
+    u = y = u_p1 = y_p1 = 0;
+    setParameters(1, 1, 0.1);
+    setOutputLimits(0, 1);
+    setOperationMode(automatic);
+}
+
+PI::PI(double K_R_, double T_I_, double T_d_) {
+    u = y = u_p1 = y_p1 = 0;
+    setParameters(K_R_, T_I_, T_d_);
+    setOutputLimits(0, 1);
+    setOperationMode(automatic);
+}
+
+void PI::setParameters(double K_R_, double T_I_, double T_d_) {
+    if (T_d_ > 0)
+        T_d = T_d_;
+    else
+        T_d = 0.1;
+    if (T_I_ > 0)
+        T_I = T_I_;
+    else
+        T_I = 1;
+    K_R = K_R_;
+}
+
+void PI::setOutputLimits(double lowerOutputLimit, double upperOutputLimit) {
+    if (upperOutputLimit > lowerOutputLimit) {
+        y_min = lowerOutputLimit;
+        y_max = upperOutputLimit;
+    }
+}
+
+void PI::setOperationMode(Mode newOperationMode) {
+    // Bumpless transfer from manual to automatic mode
+    if (operationMode == manual && newOperationMode == automatic) {
+        y = y_p1 = y_manual;
+        u = u_p1 = 0;
+    }
+    // Bumpless transfer from automatic to manual mode
+    else if (operationMode == automatic && newOperationMode == manual) {
+        y_manual = y;
+    }
+    operationMode = newOperationMode;
+}
+
+void PI::setOutputManually(double u_C) {
+    y_manual = u_C;
+}
+
+double PI::out() {
+    if (operationMode == automatic) {
+        y = y_p1 + K_R * u + K_R * (T_d / T_I - 1) * u_p1;
+    } else if (operationMode == manual) {
+        y = y_manual;
+    }
+    
+    if (y > y_max)
+        y = y_max;
+    else if (y < y_min)
+        y = y_min;
+    
+    y_p1 = y;    
+    u_p1 = u;
+    return y;
+}
+
+void PI::in(double u_) {
+    u = u_;
+}
\ No newline at end of file