diff --git a/master/slave.h b/master/slave.h
index 6654422a18879c7166324e32c58384d5e280ccf5..92be0f0f051bd3188f0456a5fb44bf64a80ffbfb 100644
--- a/master/slave.h
+++ b/master/slave.h
@@ -203,9 +203,9 @@ struct ec_slave
 
     ec_slave_state_t requested_state; /**< requested application state */
     ec_slave_state_t current_state; /**< current application state */
+    ec_slave_online_state_t online_state; /**< online state */
     unsigned int self_configured; /**< slave was configured by this master */
     unsigned int error_flag; /**< stop processing after an error */
-    unsigned int online_state; /**< online state */
 
     // addresses
     uint16_t ring_position; /**< ring position */