Nitriding Control System: Mode of Operation

 

A typical 9210 Nitriding Control system allows the user to automatically run the Nitriding cycle without requiring operator intervention.  The system will set temperature, % Dissociation/Kn, Back Pressure and Gas Flows as part of it’s recipe.  To control the % Dissociation/Kn, the 9210 has the ability to adjust the Gas flows at any step of the process.  Typically, the Ammonia flow rate is adjusted to achieve the desired % Dissociation/Kn.  This adjustment uses the Trim Enable and Trim Range variables.  These variables can be set by the recipe or manually from the Detail screen.  Trim Enable determines whether the Gas flow can be adjusted.  Trim Range is a +/- band from setpoint that the Gas Flow setpoint can be adjusted to.  For example, Ammonia Flow Setpoint = 50,Ammonia Trim Enable = Yes and Trim Range = 20.  With these settings the Ammonia Flow setpoint can be adjusted from 30 up to 70.  The amount of adjustment is determined by the % Dissociation/Kn control loop.  If the % Dissociation/Kn requires more ammonia the setpoint is increased, if less ammonia is required, the ammonia flow setpoint is decreased.