diff --git a/ontology/saref4ehaw.ttl b/ontology/saref4ehaw.ttl
index 85b2dd26202363cb00372fcf3827c91b4b354b98..1c2a72722c9518779bb9451fe928f8740c1f98ab 100644
--- a/ontology/saref4ehaw.ttl
+++ b/ontology/saref4ehaw.ttl
@@ -883,8 +883,8 @@ s4ehaw:processId rdf:type owl:DatatypeProperty ;
                  rdfs:domain s4ehaw:Process ,
 		             s4ehaw:MeasurementProcess ;
                  rdfs:range xsd:anyURI ;
-                 rdfs:comment "The process Unique ID, i.e and URI for Linked Data compatibility purposes." ,
-		              "The measurement process Unique ID, i.e and URI for Linked Data compatibility purposes." ;
+                 rdfs:comment "The process Unique ID, i.e. and URI for Linked Data compatibility purposes." ,
+		              "The measurement process Unique ID, i.e. and URI for Linked Data compatibility purposes." ;
                  rdfs:label "process id"@en .
 
 
@@ -912,6 +912,14 @@ s4ehaw:rechargeable rdf:type owl:DatatypeProperty ;
                rdfs:label "responsibility party id"@en .
 
 
+###  https://saref.etsi.org/s4ehaw/sendingFrequency
+s4ehaw:sendingFrequency rdf:type owl:DatatypeProperty ;
+                              rdfs:domain s4ehaw:Periodic ;
+                              rdfs:range xsd:float ;
+                              rdfs:comment "Defines the sending frequency at an health device level." ;
+                              rdfs:label "sending frequency"@en .
+
+
 ###  https://saref.etsi.org/s4ehaw/serialNb
 :serialNb rdf:type owl:DatatypeProperty ;
               rdfs:domain :HealthDevice ,