Inventors:
Arthur G. Black - Boulder CO
John H. Dodge - Thornton CO
Larry M. Ernst - Boulder CO
Assignee:
International Business Machines Corporation - Armonk NY
International Classification:
H05B 102
Abstract:
Control system which measures overshoot or undershoot time of a controlled variable with respect to a set value and adjusts a proportional count if the overshoot or undershoot time period exceeds fixed values. The proportional count is used to control the system output in a proportional manner, such as supplying k out of every n cycles of power, where k represents the proportional count. To prevent excessively long periods of overshoot or undershoot, an overlimit detector provides adjustments of the proportional count when the overshoot or undershoot measured time exceeds an overlimit value.
The control system has general applicability but is described in the temperature control of a fuser hot roll such as used in electrophotostatic copiers.