diff -r f859d567f94e -r 42b62867574d master/fmmu_config.h
--- a/master/fmmu_config.h	Fri Jan 22 10:11:58 2016 +0100
+++ b/master/fmmu_config.h	Fri Jan 22 13:09:43 2016 +0100
@@ -49,7 +49,8 @@
     const ec_domain_t *domain; /**< Domain. */
     uint8_t sync_index; /**< Index of sync manager to use. */
     ec_direction_t dir; /**< FMMU direction. */
-    uint32_t logical_start_address; /**< Logical start address. */
+    uint32_t logical_domain_offset; /**< Logical offset address relative to
+                domain->logical_base_address. */
     unsigned int data_size; /**< Covered PDO size. */
 } ec_fmmu_config_t;
 
@@ -58,6 +59,15 @@
 void ec_fmmu_config_init(ec_fmmu_config_t *, ec_slave_config_t *,
         ec_domain_t *, uint8_t, ec_direction_t);
 
+/**
+ * @param fmmu EtherCAT FMMU configuration.
+ * @param logical_domain_offset Logical offset address 
+        relative to domain->logical_base_address.
+ * @param data_size Covered PDO size.
+*/        
+void ec_fmmu_set_domain_offset_size(ec_fmmu_config_t *fmmu, 
+        uint32_t logical_domain_offset, unsigned data_size);
+
 void ec_fmmu_config_page(const ec_fmmu_config_t *, const ec_sync_t *,
         uint8_t *);