Bryce Williams / Mbed 2 deprecated ESP8266_pid_mtrPos_webserver_SDcard_v2

PID Motor Position Control using ESP8266 WiFi Module, US Digital E4P-100-079, LMD18200 H-Bridge Break Out, and HN-GH12-1634T 30:1 200RPM Motor

Dependencies:   4DGL-uLCD-SE PID QEI SDFileSystem mbed ESP8266_pid_mtrPos_webserver_SDcard_v2

Dependents:   ESP8266_pid_mtrPos_webserver_SDcard_v2

Files at this revision

API Documentation at this revision

Revision 9:ea167d8bdb4c, committed 2015-11-27

Comitter:
electromotivated
Date:
Fri Nov 27 15:26:42 2015 +0000
Parent:
8:e92a874cde49
Child:
10:10e747c23f6f
Commit message:
Banishing of a magic number

Changed in this revision

main.cpp Show annotated file Show diff for this revision Revisions of this file 
--- a/main.cpp	Wed Nov 25 20:51:57 2015 +0000
+++ b/main.cpp	Fri Nov 27 15:26:42 2015 +0000
@@ -78,7 +78,11 @@
 const float kp_init = 2.5;
 const float ki_init = 5.0;
 const float kd_init = 0.25;
-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();