HeaterStat Worksheet

Calculate heater resistance values

Purpose:

  • To select the proper model of CT198 for use with a catalog heater
    To calculate heater resistance values at different temperatures

 

  • Notes on specifying CT198:

  • Maximum watt density: Because the CT198 directly controls element temperature, standard watt density charts do not apply. However, when watt densities exceed 5 W/sq in, control accuracy suffers because the heater heats up too fast and the controller kicks in too soon for heat to "soak" into the part. Keep watt densities low for better control and (paradoxically) faster warmup.

  • Match calibration: Heaterstats are available match calibrated to heaters as model CT698. Customers should always prototype with CT198 first to determine the ideal setpoint. They can then return the "optimized" CT198 to Minco. We will measure its setpoint and calibrate CT698's to match (adjusting for heater resistance variations).

  • Setpoint: Be sure the setpoint range allows adjustment higher than the desired temperature.