Wifi Webserver to control the Speed of a motor using PID

Dependencies:   4DGL-uLCD-SE PID QEI SDFileSystem mbed

Revision:
3:2151f4b584b5
Parent:
2:f579e98b82de
Child:
4:05e4ebafbcaf
--- a/main.cpp	Wed Nov 25 20:49:22 2015 +0000
+++ b/main.cpp	Fri Nov 27 15:29:13 2015 +0000
@@ -78,7 +78,11 @@
 const float kp_init = 0.01;
 const float ki_init = 0.015;
 const float kd_init = 0.0001;
-const float Ts_init = 0.04;                   // 25Hz Sample Freq (40ms Sample Time)
+const float Ts_init = 0.04;                    // 25Hz Sample Freq (40ms Sample Time)
+const float Ts_PID_CALLBACK = Ts_init/2.0;     // Update Motors and sensers twice as 
+                                               // fast as PID sample rate, ensures
+                                               // PID feedback is upto date every 
+                                               // time PID calculations run
 
 PID pid(&setpoint, &feedback, &output, output_lower_limit, output_upper_limit,
         kp_init, ki_init,  kd_init, Ts_init);
@@ -171,7 +175,7 @@
     // Update sensors and feedback twice as fast as PID sample time
     // this makes pid react in real-time avoiding errors due to 
     // missing counts etc. 
-    motor.attach(&pid_callback, Ts_init/2.0);
+    motor.attach(&pid_callback, Ts_PID_CALLBACK);
     
     // Start PID sampling
     pid.start();