What is claimed is:
1. A method of controlling a heating system comprising:
providing at least one heater assembly including an outer heating surface for heating a heating target outside the outer heating surface, the heater assembly comprising a plurality of heater units disposed along a length of the heater assembly and enclosed within the outer heating surface of the heater assembly, and a plurality of power conductors extending through the plurality of heater units, each heater unit including a resistive heating element defining an independently controlled heating zone;
supplying power to the resistive heating elements in the independently controlled heating zones through the plurality of power conductors, the power conductors electrically connected to the resistive heating element in each of the independently controlled heating zones;
determining a temperature within the independently controlled heating zones; and
automatically modulating power supplied to the resistive heating element in each of the independently controlled heating zones through the power conductors in response to the determined temperature by using a controller to change a heat output of at least one of the heating zones to provide a desired heat distribution along a length of the outer heating surface of the heater assembly.
2. The method according to claim 1 further comprising comparing the determined temperatures to target temperatures and modulating the power supplied to achieve the target temperatures.
3. The method according to claim 1 further comprising using a scaling factor to adjust the modulating power.
4. The method according to claim 3 further comprising using the scaling factor as a function of a heating capacity of each heating zone.
5. The method according to claim 1 further comprising turning off at least one of the independently controlled heating zones based on an anomalous condition.
6. The method according to claim 1 , wherein the temperature is determined in each of the independently controlled heating zones.
7. The method according to claim 1 , wherein when the determined temperature in at least one of the independently controlled heating zones is deviated from a target temperature, power is modulated to at least one other heating zone to provide the desired heat distribution along the length of the outer heating surface of the heating assembly.
8. The method according to claim 1 , wherein the determining of the temperature includes determining the temperature using a change in resistance of a resistive heating element of at least one of the heater units.
9. The method according to claim 1 , wherein the power is modulated to the independently controlled heating zones as a function of at least one of received signals, a model, and as a function of time.
10. The method according to claim 1 , further comprising calibrating the heating system according to the following steps:
operating the heater system in at least one mode of operation;
controlling the heater system to activate at least one of the plurality of independently controlled heating zones to generate a desired temperature;
collecting and recording data for the at least one of the plurality of independently controlled heating zones and the at least one mode of operation;
accessing the recorded data to determine operating specifications for the heating system when the at least one of the plurality of independently controlled heating zones is turned off; and
operating the heating system with at least one of the plurality of independently controlled heating zones being turned off.
11. The method according to claim 10 , wherein the data is selected from the group consisting of power levels and temperature information.
12. A method of controlling a heater system comprising:
providing a plurality of heater assemblies each including an outer heating surface for heating a heating target outside the outer heating surface, more than one of the heater assemblies each comprising a plurality of heater units disposed along a length of the more than one of the heater assemblies and enclosed within a respective one of the outer heating surfaces of the plurality of heater assemblies and a plurality of power conductors extending through the plurality of heater units, more than one of the heater units including at least one resistive heating element defining at least one independently controlled heating zone;
supplying power to the resistive heating elements in the independently controlled heating zones;
determining a temperature of the plurality of heater assemblies; and
automatically modulating power supplied to the resistive heating elements in the independently controlled heating zones in response to the determined temperature by using a controller to reduce a heat output of at least one of the heating zones to provide a desired heat distribution along a length of the outer heating surfaces of the more than one of the heater assemblies.
13. The method according to claim 12 further comprising providing a total of m×k independently controlled heating zones, wherein the number of the heater assemblies is k, and the number of the independently controlled heating zones of each of the heater assemblies is m.
14. The method according to claim 12 further comprising turning off at least one of the independently controlled heating zones while continuing to supply power to remaining independently controlled heating zones.
15. The method according to claim 12 , wherein temperature is determined within at least one of the independently controlled heating zones and power is modulated based on the determined temperature within the independently controlled heating zone.
16. The method according to claim 15 further comprising comparing the detected temperature to a target temperature and modulating the power supplied to achieve the target temperature.
17. The method according to claim 12 further comprising using a scaling factor to adjust the modulating power.
18. The method according to claim 12 , wherein power supplied to the plurality of independently controlled heating zones is varied based on a predetermined heat distribution across the heater system.
19. A method of controlling a heater system comprising:
providing a plurality of heater assemblies each including an outer heating surface for heating a heating target outside the outer heating surface, more than one of the heater assemblies comprising a plurality of heater units disposed along a length of the respective ones of the more than one of the heater assemblies and enclosed within the respective one of the outer heating surfaces of the plurality of heater assemblies and a plurality of power conductors extending through the plurality of heater units, more than one of the heater units including at least one resistive heating element defining at least one independently controlled heating zone;
supplying power to the resistive heating elements in the independently controlled heating zones;
determining at least one of heating conditions and heating requirements; and
automatically modulating power supplied to the resistive heating element in each of the independently controlled heating zones in response to the at least one of heating conditions and heating requirements by using a controller to change a heat output of at least one of the heating zones to provide a desired heat distribution along a length of the outer heating surfaces of the more than one of the heater assemblies.
20. A method of controlling a heating system c