To control temperature, many different parameters can be tracked. Taking the area under the temperature curve multiplied by time, Dt can be calculated and graphed as an indicator of the amount of thermal energy in a drive process, as shown in Figure 7. In that case, average power did not deviate substantially over 500 runs, showing good element performance and thermal packing. Control System Results AFD has been running on all furnaces for more than two years with excellent results. When a furnace alarm indicates that an AFD parameter is out of limits, the operator contacts an engineer or technician to diagnose the problem.
Most alarms are early indicators that a tool requires maintenance.
For many parameters, early warning allows production to schedule downtime so that repairs can be made when convenient. Also, tracking parameters with AFD facilitates preventive maintenance on tools, which can reduce downtime. Dt as an indicator of the amount of thermal energy in a drive process. Tracking of power during an oxidation step, indicating that average power did not deviate substantially over 500 runs and that good element performance and thermal packing were maintained. MFC drift detection has led to a reduction in misdiagnoses of MFC failures, all but eliminating unnecessary gas delivery system repairs and long tool requalifications.