Mains Water Pump House - Slough Heat and Power
Power , Water
Allen Bradley SLC500, PanelView Plus 600, Intouch, Radio Communications
Design and supply of a new Control Panel and control software to replace an outdated relay logic system at the Mains Water Pumphouse at Slough Power Station.
The old system consisted of 4 pumps and control valves supplying water to Slough Industrial Estate. The system is required to maintain the delivery pressure by calling duty/assist pumps and modulating the pump delivery valves. The original system only had a semi-automatic mode which required a lot of manual intervention.
The new design required full automatic control and fault tolerant operation utilising the 4 pumps and alternative instruments.
The relay control panel was replaced with an Allen Bradley SLC505 (the client’s preferred PLC system) and a PanelView Plus 600 HMI. The HMI is connected locally using Ethernet. The PLC is fitted with a selection of input and output cards to monitor and control the plant instrumentation and equipment. The PLC system is also fitted with a serial Modbus card for communications to a radio system. The radio system transmits the plant data to an Intouch SCADA System in the works control room.
Supervisory and Operator controls are also provided at the SCADA workstation.
The system was designed to maintain a pressure setpoint in the delivery manifolds and the output of pumps was controlled by modulating delivery valves. The duty delivery valve is controlled with a PID algorithm and the delivery valves for the assist pumps are modulated to provide a base load. The duty/assist logic monitors the pump current to determine when additional pumps are required to operate.