--- a/master/datagram.c	Thu Jan 12 12:14:33 2012 +0100
+++ b/master/datagram.c	Thu Jan 12 13:55:15 2012 +0100
@@ -88,6 +88,7 @@
 void ec_datagram_init(ec_datagram_t *datagram /**< EtherCAT datagram. */)
 {
     INIT_LIST_HEAD(&datagram->queue); // mark as unqueued
+    datagram->device_index = EC_DEVICE_MAIN;
     datagram->type = EC_DATAGRAM_NONE;
     memset(datagram->address, 0x00, EC_ADDR_LEN);
     datagram->data = NULL;