diff --git a/IOB-WIN/IobFanuc.cs b/IOB-WIN/IobFanuc.cs
index 58bc492f..dc9afc5f 100644
--- a/IOB-WIN/IobFanuc.cs
+++ b/IOB-WIN/IobFanuc.cs
@@ -172,7 +172,7 @@ namespace IOB_WIN
       if (verboseLog) lg.Info("inizio read semafori");
       parentForm.sIN = Semaforo.SV;
       // leggo SEMAFORI, leggo da Y8 ...leggo 3 bit in Y8..Y10  HARD CODED, rendere parametrico!!!
-      byte[] MemBlock = new byte[3];
+      byte[] MemBlock = new byte[4];
       // Red: Y8.4 | Yellow: Y8.5 | Green Y8.6 | WrkZone Y8.7 | All DoorsClosed: Y10.5
       int memIndex = 8;
       inizio = DateTime.Now;