diff --git a/states.h b/states.h
--- a/states.h
+++ b/states.h
@@ -29,6 +29,7 @@ typedef union
         int32_t setpoint_steam;
         uint32_t control_mode;
         uint32_t plant_type;
+        uint32_t hysteresis;
     } val;
 
     uint16_t data[128];
@@ -44,6 +45,7 @@ enum state {
     
     STATE_SETMODE,
     STATE_SETPLANTTYPE,
+    STATE_SETHYSTERESIS,
     STATE_SETP,
     STATE_SETI,
     STATE_SETD,