diff --git a/src/iec61850/server/mms_mapping/control.c b/src/iec61850/server/mms_mapping/control.c
index 55f7e1bd..cb09e8a0 100644
--- a/src/iec61850/server/mms_mapping/control.c
+++ b/src/iec61850/server/mms_mapping/control.c
@@ -279,6 +279,7 @@ copyControlValuesToTrackingObject(MmsMapping* self, ControlObject* controlObject
             }
 
             if (operVal) {
+
                 if (trkInst->Test) {
                     MmsValue_update(trkInst->Test->mmsValue, getOperParameterTest(operVal));
                 }
@@ -1911,6 +1912,13 @@ Control_writeAccessControlObject(MmsMapping* self, MmsDomain* domain, char* vari
 
         if (controlObject->ctlModel == 4) {
 
+            if (controlObject->sbow) {
+                if (MmsValue_update(controlObject->sbow, value) == false) {
+                    if (DEBUG_IED_SERVER)
+                        printf("IED_SERVER: SBOw - type mismatch\n");
+                }
+            }
+
             MmsValue* ctlVal = getCtlVal(value);
 
             if (ctlVal != NULL) {