Two VC-22D electronic valve controllers, control the operation of the two 24” (600mm) dual solenoid control valves by sending electrical pulses to the opening solenoid, allowing water to flow out from the valve cover chamber, which in turn, allows the valve to open slightly with each pulse, or to the closing solenoid, allowing water to flow into the valve cover chamber, which in turn, allows the valve to close slightly with each pulse.
The VC-22D uses a customized Valve App for the logic controls. This allows for complete control of the valve using intuitive programming screens, allowing for easy and fast programming. Complete capabilities allow either stand-alone operation or easy integration into the SCADA system. It works on the principle of modulating level control by position with the valves working in a single or dual valve operation. The controllers are interlocked so operation can be switched over periodically between the two valves.
On automatic mode, the lead valve controller initiates the valves' operation based on the current pond level. When levels are within the pond level set point, the lead valve is in the closed position with the lead valve controller sending a digital command to the standby controller to keep the standby valve closed. As the pond level drops below the level set point, the lead valve is actuated by the controller to open and modulate to the specified target position. The target position is determined by a level versus position control curve programmed into the Valve App.
If the pond level continues to drop and the target position reaches a pre-set switch high position set point, the operation switches from single to dual valves, with the lead valve controller removing the digital command to the standby controller, allowing the standby valve to open and modulate to the specified target position. The lead valve then modulates to control at the same target position as the standby valve.
As the pond level rises and the target position reaches a pre-set switch low position set point, the operation switches back to single, with the lead valve controller sending a digital command to the standby controller to close the valve and keep it close and the lead valve modulating to control at the specified target position.
The valve closes as the pond level reaches the pre-set level set point.
A manual mode is also available on both controllers, wherein you can set the position you want the valve to modulate to. This mode is suited for initial pond filling to keep the valves from working continuously at or near its pre-determined maximum velocity.
In the event of a loss of pond level feedback, an action is programmed to slowly close the valve or valves. Further, a high (overflow) level switch sends a signal to SCADA, which then sends a digital signal to the VC-22D controller to close the valve or valves.
If the flow rate goes above a pre-determined flow, an action is programmed to keep the opening solenoid from pulsing but allows the closing solenoid to operate as normal. This is to limit the flow velocity across the valve during peak operation.
Cla-Val is one of the industry's leading manufacturers of automatic control valves & flow control solutions. Learn more at www.cla-val.com.