diff -r af21f0bdc7c9 -r 2b9c78543663 examples/rtai/rtai_sample.c
--- a/examples/rtai/rtai_sample.c	Thu Sep 06 14:21:02 2012 +0200
+++ b/examples/rtai/rtai_sample.c	Mon Nov 03 15:20:05 2014 +0100
@@ -234,8 +234,8 @@
 
         rt_sem_wait(&master_sem);
         ecrt_domain_queue(domain1);
+        ecrt_master_send(master);
         rt_sem_signal(&master_sem);
-        ecrt_master_send(master);
 
         rt_task_wait_period();
     }
@@ -243,18 +243,30 @@
 
 /*****************************************************************************/
 
-void request_lock_callback(void *cb_data)
+void send_callback(void *cb_data)
 {
     ec_master_t *m = (ec_master_t *) cb_data;
-    rt_sem_wait(&master_sem);
-}
-
-/*****************************************************************************/
-
-void release_lock_callback(void *cb_data)
+
+    // too close to the next real time cycle: deny access...
+    if (get_cycles() - t_last_cycle <= t_critical) {
+        rt_sem_wait(&master_sem);
+        ecrt_master_send_ext(m);
+        rt_sem_signal(&master_sem);
+    }
+}
+
+/*****************************************************************************/
+
+void receive_callback(void *cb_data)
 {
     ec_master_t *m = (ec_master_t *) cb_data;
-    rt_sem_signal(&master_sem);
+
+    // too close to the next real time cycle: deny access...
+    if (get_cycles() - t_last_cycle <= t_critical) {
+        rt_sem_wait(&master_sem);
+        ecrt_master_receive(m);
+        rt_sem_signal(&master_sem);
+    }
 }
 
 /*****************************************************************************/
@@ -275,12 +287,12 @@
 
     master = ecrt_request_master(0);
     if (!master) {
-        ret = -EBUSY; 
+        ret = -EBUSY;
         printk(KERN_ERR PFX "Requesting master 0 failed!\n");
         goto out_return;
     }
 
-    ecrt_master_callbacks(master, request_lock_callback, release_lock_callback, master);
+    ecrt_master_callbacks(master, send_callback, receive_callback, master);
 
     printk(KERN_INFO PFX "Registering domain...\n");
     if (!(domain1 = ecrt_master_create_domain(master))) {