diff --git a/PVSFormat/AddZone.Designer.cs b/PVSFormat/AddZone.Designer.cs
index a0a9a45..fce6e30 100644
--- a/PVSFormat/AddZone.Designer.cs
+++ b/PVSFormat/AddZone.Designer.cs
@@ -58,7 +58,7 @@ private void InitializeComponent()
             // zoneIdNumericUpDown
             // 
             zoneIdNumericUpDown.Location = new System.Drawing.Point(42, 32);
-            zoneIdNumericUpDown.Maximum = new decimal(new int[] { 512, 0, 0, 0 });
+            zoneIdNumericUpDown.Maximum = new decimal(new int[] { 511, 0, 0, 0 });
             zoneIdNumericUpDown.Name = "zoneIdNumericUpDown";
             zoneIdNumericUpDown.Size = new System.Drawing.Size(100, 23);
             zoneIdNumericUpDown.TabIndex = 2;