diff --git a/PID.c b/PID.c
index 877c32d..4f41e6b 100644
--- a/PID.c
+++ b/PID.c
@@ -1,7 +1,19 @@
+/*
+ * PID Controller implementation
+ *
+ * Features:
+ *  - Proportional, Integral, Derivative control
+ *  - Anti-windup via integrator clamping
+ *  - Band-limited differentiator (derivative on measurement)
+ *
+ * Suitable for embedded and real-time systems.
+ */
 #include "PID.h"
 
 void PIDController_Init(PIDController *pid) {
 
+	if (pid == 0) return;
+	
 	/* Clear controller variables */
 	pid->integrator = 0.0f;
 	pid->prevError  = 0.0f;