diff --git a/tools/esp8266/hmDefines.h b/tools/esp8266/hmDefines.h
index 28615ed7..baec0f75 100644
--- a/tools/esp8266/hmDefines.h
+++ b/tools/esp8266/hmDefines.h
@@ -125,7 +125,7 @@ const byteAssign_t hm1chAssignment[] = {
     { FLD_PRA, UNIT_VA,  CH0, 20, 2, 10   },
     { FLD_F,   UNIT_HZ,  CH0, 16, 2, 100  },
     { FLD_T,   UNIT_C,   CH0, 26, 2, 10   },
-    { FLD_ALARM_MES_ID,   UNIT_NONE,   CH0, 28, 2, 1 },
+    { FLD_ALARM_MES_ID,   UNIT_NONE,   CH0, 24, 2, 1 },
     { FLD_YD,  UNIT_WH,  CH0, CALC_YD_CH0,  0, CMD_CALC },
     { FLD_YT,  UNIT_KWH, CH0, CALC_YT_CH0,  0, CMD_CALC },
     { FLD_PDC, UNIT_W,   CH0, CALC_PDC_CH0, 0, CMD_CALC },