diff --git a/src/main/java/com/iot/modbus_rtcp/utils/HexUtil.java b/src/main/java/com/iot/modbus_rtcp/utils/HexUtil.java
index f3359ca..ffa3b83 100644
--- a/src/main/java/com/iot/modbus_rtcp/utils/HexUtil.java
+++ b/src/main/java/com/iot/modbus_rtcp/utils/HexUtil.java
@@ -23,7 +23,7 @@ public class HexUtil {
     }
 
     public static int hashPartition(String key, int partition) {
-        return key.hashCode() % partition;
+        return Math.abs(key.hashCode() % partition);
     }
 
     public static void main(String[] args) {