The CAPTROL® controller is a microprocessor-based controller designed to control chemical feed with a Capital Controls automatic gas feeder valve in water or wastewater applications. Standard features include: three chlorination and two dechlorination control modes; built-in multiplier for feed forward dechlorination control; automatic transfer from compound loop control when residual or flow signal is lost; bumpless transfer between manual and automatic control; digital displays; alarm indicators; alarm contacts; control switch inputs; and gas flow output signal.
The controller automatically positions the control valve to maintain desired feed rate or chlorine residual based on electrical input signals from the flowmeter or chlorine residual analyzer. A 4-20 mAdc output signal representing gas flow can be used as an input to computer control systems, for ratio control of chlorination and dechlorination systems, or for remote indication, recording, or totalizing of gas flow.
The controller is field-configurable for chlorination (flow proportioning, residual or compound loop control) or
dechlorination (flow proportioning or feed forward control using the built-in multiplier). Residual control is accomplished by a single-mode integral control loop with adjustable process lag time. All setup, tuning and control adjustment is done from the front panel with factory calibration of input and output signals. The microprocessor design simplifies controller tuning to a maximum of three adjustments: dosage, process lag time and integral. Front panel alarm indicators and internal contacts are provided for high and low residual set point deviation and low process water flow.