diff --git a/IOB-WIN-NEXT/IobOmron.cs b/IOB-WIN-NEXT/IobOmron.cs
index c4c9d301..93e5dd6f 100644
--- a/IOB-WIN-NEXT/IobOmron.cs
+++ b/IOB-WIN-NEXT/IobOmron.cs
@@ -522,7 +522,7 @@ namespace IOB_WIN_NEXT
         /// OVerride metodo x scrittura parametri su PLC
         /// </summary>
         /// <param name="updatedPar"></param>
-        protected override void plcWriteParams(List<objItem> updatedPar)
+        protected override void plcWriteParams(ref List<objItem> updatedPar)
         {
             int valInt = 0;
             if (updatedPar != null)
diff --git a/IOB-WIN-NEXT/IobOpcUaEwon.cs b/IOB-WIN-NEXT/IobOpcUaEwon.cs
index ee291d4a..a280dd4e 100644
--- a/IOB-WIN-NEXT/IobOpcUaEwon.cs
+++ b/IOB-WIN-NEXT/IobOpcUaEwon.cs
@@ -143,7 +143,7 @@ namespace IOB_WIN_NEXT
         /// Effettua vera scrittura parametri
         /// </summary>
         /// <param name="updatedPar"></param>
-        protected override void plcWriteParams(List<objItem> updatedPar)
+        protected override void plcWriteParams(ref List<objItem> updatedPar)
         {
 #if false
             if (!testDone)
diff --git a/IOB-WIN-NEXT/IobSimula.cs b/IOB-WIN-NEXT/IobSimula.cs
index 827fcf51..685c346b 100644
--- a/IOB-WIN-NEXT/IobSimula.cs
+++ b/IOB-WIN-NEXT/IobSimula.cs
@@ -524,7 +524,7 @@ namespace IOB_WIN_NEXT
         /// Salvo valori PLC
         /// </summary>
         /// <param name="updatedPar"></param>
-        protected override void plcWriteParams(List<objItem> updatedPar)
+        protected override void plcWriteParams(ref List<objItem> updatedPar)
         {
         }