Operation and Control

Process control for the raw water pumping system is provided by the PCS, through a Remote Terminal Unit (RTU-100) located in the existing Raw Water Intake Pump Station and RTU-101 located at the Control Valve Vault. The raw water pumps operate based on Plant START and STOP commands from the PCS. The RW pump operation can be accomplished in manual (HAND) or automatic (AUTO) mode. The Plant generally operates in HAND mode, and the individual pumps are operator selected and placed into HAND mode at the PCS based on their production rate to most nearly match the Plant production rate.

Local Control:

When the HAND / OFF / AUTO switch on the local panel (RTU-100) is in the HAND position, the selected pump (P-100-1, 2, 3, and 4) starts immediately. The PCS also allows HAND operation of the pumps. HAND initiation of Plant START will start the raw water pumps if they are in AUTO.

PLC Control:

Automatic operation requires that AUTO is selected from the raw water pump HAND / AUTO / OFF switch on the PCS and that AUTO is selected from the HAND / OFF / AUTO switch on the local panel (RTU-100). The operator selects a combination of pumps to provide the desired rate and placed them in AUTO on the PCS. Upon a Plant START command, the PCS starts the selected RW pumps. 

PCS / HMI Configuration:

  • Status Display:
    • Pump HAND / OFF / AUTO local panel switch indication (each).
    • Pump RUN / OFF status (each).
    • Delay till next pump called.
    • Raw Water Flow (in vault) indication.
    • Raw Water pressure (upstream of valve) indication.
    • Raw Water pressure (downstream of valve) indication.
    • Control Valve OPEN / CLOSED status.
    • Raw Water flow (in WTP) indication.
    • Raw Water 1 Turbidity indication.
  • Raw Water 1 pH indication.
  • RW pH 2 indication (after chemical addition).
    • Raw Water pressure (in WTP) indication.
  • Operator Entries:
    • Pump HAND / OFF / AUTO PCS selector (each).
    • Delay seconds between pump calls.
    • Raw Water flow (in vault) HIGH-HIGH alarm setpoint.
    • Raw Water flow (in vault) HIGH alarm setpoint.
    • Raw Water flow (in vault) LOW alarm setpoint.
    • Raw Water flow (in vault) LOW-LOW alarm setpoint.
    • Control Valve OPEN / CLOSE / AUTO selector.
    • Raw Water pressure (upstream of valve) HIGH-HIGH alarm setpoint.
    • Raw Water pressure (upstream of valve) HIGH alarm setpoint.
    • Raw Water pressure (downstream of valve) HIGH-HIGH alarm setpoint.
    • Raw Water pressure (downstream of valve) HIGH alarm setpoint.
    • Raw Water flow (in WTP) HIGH-HIGH alarm setpoint.
    • Raw Water flow (in WTP) HIGH alarm setpoint.
    • Raw Water flow (in WTP) LOW alarm setpoint.
    • Raw Water flow (in WTP) LOW-LOW alarm setpoint.
    • Raw Water 1 turbidity HIGH-HIGH alarm setpoint.
    • Raw Water 1 turbidity HIGH alarm setpoint.
    • Raw Water 1 pH HIGH alarm setpoint.
    • Raw Water 1 pH LOW alarm setpoint.
    • Raw Water pressure (in WTP) HIGH-HIGH alarm setpoint.
    • Raw Water pressure (in WTP) HIGH alarm setpoint.
  • Alarms:
    • Pump FAIL (each).
    • Raw Water flow (in vault) ALARM (high-high, high, low, and low-low).
    • Raw Water pressure (upstream of valve) ALARM (high-high and high).
    • Raw Water pressure (downstream of valve) ALARM (high-high and high).
    • Raw Water flow (in WTP) ALARM (high-high, high, low, and low-low).
    • Raw Water 1 turbidity ALARM (high-high and high).
    • Raw Water 1 pH HIGH ALARM (high and low).
    • Raw Water pressure (in WTP) ALARM (high-high and high).
  • Historical Trending:
    • Raw Water Flow (in control valve vault).
    • Raw Water Flow (in WTP).
    • Raw Water 1 Turbidity.
    • Raw Water 1 pH.