diff --git a/master/fsm_master.c b/master/fsm_master.c
index 909c0115..b4f8f2ad 100644
--- a/master/fsm_master.c
+++ b/master/fsm_master.c
@@ -989,11 +989,12 @@ void ec_fsm_master_state_scan_slave(
     master->scan_index = master->slave_count;
     wake_up_interruptible(&master->scan_queue);
 
-    ec_master_calc_dc(master);
-
     // Attach slave configurations
     ec_master_attach_slave_configs(master);
 
+    // Calculate DC (needs attached slaves due to reference clock selection)
+    ec_master_calc_dc(master);
+
 #ifdef EC_EOE
     // check if EoE processing has to be started
     ec_master_eoe_start(master);