MIC 1400 Manual
Edition 1
36
Time Proportioning Control 4.5
Time Proportioning control can be implemented with a SPDT relay or SSR
driver. Time proportioning control can be selected for either Output 1 or
Output 1 and Output 2, depending on hardware configuration. Time pro-
portioning control is accomplished by cycling the output on and off during a
prescribed period of time when the process variable is within the propor-
tional band.
Ex:
Calculated output % = 40%; Cycle time adjustment = 32 seconds
Output on time = .4 x 32 = 12.8 seconds
Output off time = .6 x 32 = 19.2 seconds
When the unit is operating in the Control mode, the control algorithm deter-
mines the output % required to correct for any difference between the pro-
cess value and the setpoint. The output calculation is affected by Tune
mode parameter adjustments. See Figure 4-1 (page 37) for proportional
bandwidth effect on the output.
