What is Two-Mode Control?

Operates on same basic proportional band principle as one-mode, but introduces an additional reset control action which depends upon the accumulated error x time product (integral). The sum of the error and reset signals continuously act to make the actual error signal smaller. (i.e. controls to the selected control point.)

Three-Mode Control Similar to two-mode control, but with an additional rate sensing (derivative) action which reduces tendency to over-shoot a control setpoint by anticipating the approach of a zero-value error signal and initiating a control response reversal before the sensed temperature actually gets there.