Swimming Pool Technical Equipment Automation Systems

We have completed the design documentation for the automation system of swimming pool technical equipment

swimming pool automation control system project

Description of Swimming Pool Technical Equipment Automation System

Abbreviations Used in the Text

AS - Automation System
DE - Discharge Tank
OE - Overflow Tank
FM - Five-valve Module
UV Lamp - Ultraviolet Lamp

Pool Automation System Project

The swimming pool technical equipment automation system is designed based on a programmable controller and five expansion modules. The system is implemented as part of an automation cabinet and dispatch control screen, and integrated into the existing estate automation system.

Automation scope:

Measurement

Water temperature at pool outlet
Water level in overflow tank
Level in discharge tank
Liquid level in coagulation station tank
Level in pH station tank
Level in H₂O₂ tank
Water pH
Ozone content
Pressure at filtration column inlet
Pressure at column outlet
Water flow rate

On/Off Control:

Opening and closing of FM valve
Water fill valve for overflow tank
Heat exchanger coolant valve
Power on/off for coagulation station
Power for pH station
Power for H₂O₂ station
Ozonator
UV lamp power
Heat exchanger coolant pump
Circulation pump

Activation Signaling:

Circulation pump magnetic starter
Heat exchanger pump magnetic starter
Water fill valve magnetic starter
pH station
H₂O₂ station
Coagulation station
Ozonator
UV lamp
Valve closed end position

Regulation

Pool water temperature
Overflow tank level
Discharge tank level

NOTE: Regulation of other parameters is performed by respective stations (pH, H₂O₂, ozonator).

AUTOMATION CABINET

The automation cabinet diagram provides for connection of peripheral equipment that ensures parameter measurement and control of pool technical equipment systems. Control devices and signal lamps are installed on the cabinet doors, directly participating in the automation system operation algorithm. Detailed description of internal and external cabinet connections is provided in the Working Project.

Control Devices and Signal Lamps

The appearance of automation and dispatch cabinet doors is shown in Figure 2.1. Control devices and signal lamps are numbered according to their functional purpose description.

Lamp Test button simultaneously lights all lamps to check their functionality. Recommended to press during each cabinet inspection.
Three-position switch for Circulation Pump Control allows manual pump start (M position), turn off (O position), or switch to automatic mode (A position). Includes alarm reset function by switching to off position then to automatic mode.
Green signal lamp for Circulation Pump Operation indicates activation of circulation pump magnetic starter.
Red signal lamp for Thermal Protection Activation
Three-position switch for Heat Exchanger Pump Control allows manual pump start, turn off, or switch to automatic mode.
Green signal lamp for Heat Exchanger Pump Operation indicates activation of heat exchanger pump magnetic starter
Three-position switch for Water Fill Valve Control allows manual valve opening, closing, or switch to automatic mode.
Green lamp "Water Fill Valve Operation" indicates activation of water fill valve magnetic starter.
Three-position switch "pH Station Control" enables manual power supply to pH station, turn off, or switch to auto mode.
Green lamp "pH Station Operation" indicates activation of pH station magnetic starter
Three-position switch "H₂O₂ Station Control" enables manual power supply to H₂O₂ station, turn off, or switch to automatic mode.
Green lamp "H₂O₂ Station Operation" indicates activation of H₂O₂ station magnetic starter
Three-position switch "Coagulation Station Control" enables manual power supply to coagulation station, turn off, or switch to automatic mode.
Green signal lamp "Coagulation Station Operation" indicates activation of coagulation station magnetic starter
Three-position switch "Servomotor 1 Control" switches valve 1 control to manual mode, off, or automatic mode.
Two-position switch "Open/Close" for servomotor 1 closes (Close position) or opens valve 1 (Open position) only in manual control mode.
Green signal lamp "Servomotor 1 Open" indicates activation of valve open end position sensor
Red signal lamp "Servomotor 1 Closed"
Three-position switch "Servomotor 2 Control" switches valve 2 control to manual mode, off, or automatic mode.
Two-position switch "Open/Close" for servomotor 2 closes (Close position) or opens valve 2 (Open position) only in manual control mode.
Three-position switch "Ozonator Control" enables manual power supply to ozonator, turn off, or switch to automatic mode.
Green signal lamp "Ozonator Operation" indicates activation of ozonator magnetic starter
Three-position switch "UV Lamp Control" enables manual power supply to UV lamp, turn off, or switch to automatic mode.
Green signal lamp "UV Lamp Operation" indicates UV lamp activation

pool dispatch control system

To start the system in automatic mode, all three-position switches must be set to automatic mode position.

NOTE: When necessary, it is allowed to switch station and ozonator three-position switches to off position during pool automatic operation. Other equipment will continue operating according to the programmed sequence with stations or ozonator excluded from the process.

Pool Operation Mode Algorithms

Four preset pool operation modes are provided:

System Stop
Filtration Process
Backwash Process
Compaction Process

System Stop

Defines system state where control and regulation processes are stopped. All equipment is off, valves are closed. Measurement and status information collection continues. When transitioning to "System Stop" from other states, devices are turned off and command to close FM valves is generated.

"System Stop" state can be initiated by user by setting point value to "0". This state can also be initiated programmatically without user participation in cases of:

Switching between any two of the three other states
Critical alarm (except station and ozonator alarms)
Technical equipment room flooding

To exit System Stop state when no alarms are present, assign another value to PROCESS_MODE point corresponding to one of the three other states. Recommended to switch pool systems to "System Stop" state during pool equipment maintenance procedures and when detecting emergency situations not covered by the program, or when pool operation is not required.

Filtration Process

Defines system state where FM valves are in position for water circulation through filtration column and subsequent supply to pool basin, circulation pump is running, and water treatment device control algorithms are active.

When transitioning to filtration state, a delay is executed during which equipment will remain in or be switched to "System Stop" state, but water fill valve operation algorithm will be started. The delay is determined by a one-minute timer for each new start and by the allowable level setting in OE for starting filtration mode when actual level is below it. After delay completion, FM valves will be switched to position required by filtration mode (however valve position can be changed by user by setting appropriate state to points specified in project table). After FM setup, circulation pump is started within 10 seconds. Upon response from circulation pump magnetic starter status, coagulation station, UV lamp, heat exchanger, ozonator, pH and H₂O₂ station operation algorithms are simultaneously started.

"Filtration Process" state can be initiated by user by setting point value to "1". This state cannot be initiated programmatically but can be paused with subsequent automatic restart in cases of:

Pool systems night rest
Insufficient water level in OE

In both cases, water fill valve operation algorithm will not be paused.

Filtration can also be stopped without automatic restart in cases of:

Critical alarm
Technical equipment room flooding

To exit "Filtration Process" state, assign another value to the point corresponding to one of the three other states.

Backwash Process

Defines system state where FM valves are in position for water circulation through filtration column in reverse direction and subsequent discharge to DE, circulation pump is running, other equipment is off.

When transitioning to backwash state, a delay is executed during which equipment will remain in or be switched to System Stop state. The delay is determined by a one-minute timer for each new start and by allowable level settings in OE and DE for starting backwash process when actual water level in OE is below its setting, and water level in DE is above. Then backwash will start only when water level in OE reaches specified setting, and in DE by level decrease below permitting setting. After delay completion, FM valves will be switched to position required by backwash mode (however valve position can be changed by user by setting appropriate state to points specified in project). After FM setup, circulation pump is started within 10 seconds.

"Backwash Process" state can be initiated by user by setting point value to "2". This state cannot be initiated programmatically but can be paused with subsequent automatic restart in cases of:

Insufficient water level in OE
Reaching prohibiting water level in DE

Start will not be executed if prohibiting level setting of DE is set lower than permitting level setting of DE.

Backwash can also be stopped without automatic restart in cases of:

Critical alarm
Technical equipment room flooding

To exit "Backwash Process" state, assign another value to the point corresponding to one of the three other states. Recommended to perform backwash process when filter pressure differential reaches setting (setting is user-defined) and after specified number of days since last backwash procedure. Other recommendations are determined by operational requirements.

When backwash mode stops due to reaching prohibiting level in DE, it is necessary to start compaction process, otherwise system will remain in waiting mode for DE emptying to repeat backwash process.

Compaction Process

When transitioning to compaction state, a delay is executed during which equipment will remain in or be switched to "System Stop" state. The delay is determined by a three-minute timer for each new start and by allowable level settings in OE and DE for starting compaction process when actual water level in OE is below its setting, and water level in DE is above. Then compaction will start only when water level in OE reaches specified setting, and in DE by level decrease below permitting setting. After delay completion, FM valves will be switched to position required by compaction mode (however valve position can be changed by user by setting appropriate state to points specified in table). After FM setup, circulation pump is started within 10 seconds.

To exit "Compaction Process" state, assign another value to the point corresponding to one of the three other states. Recommended to perform compaction process immediately after backwash process and according to pool equipment operational requirements. When compaction mode stops due to reaching prohibiting level in DE, it is necessary to initiate "System Stop" or "Filtration Process" state, otherwise system will remain in waiting mode for DE emptying to repeat compaction process.

Automation Equipment

Operation according to described algorithms is possible only when three-position switches on the cabinet are set to "auto" position.

FM Valve

Valve position is set by pool operation mode. Current valve status is indicated by signals from valve servomotor end position sensors. When status doesn't meet mode requirements, valve actuator control is performed, monitoring disappearance of initial position signal and appearance of achieved position signal. Achieving required position generates valve readiness response. Presence of initial position signal for more than three seconds is considered as jamming, and absence of achieved position signal for more than twenty seconds as servomotor failure. In these cases, valve is set to alarm state.

Circulation Pump

Starts only in three modes:

Filtration process
Backwash process
Compaction process

Start condition is valve readiness for operation in selected mode. If start signal is present but no response from magnetic starter within five seconds, circulation pump is set to alarm state.

Heat Exchanger

Starts only in filtration mode with operating circulation pump. Heats water to required value determined by setting, by simultaneous start of coolant pump and opening of coolant valve. Switching logic is relay type with hysteresis by temperature, also set by setting. When turning off, coolant pump stops first, then after fifteen seconds coolant valve closes. If start signal is present but no response from magnetic starter within five seconds, heat exchanger is set to alarm state.

UV Lamp, Ozonator, pH Station, H₂O₂ Station, Coagulation Station:

Operates only in filtration mode together with circulation pump. If start signal is present but no response from magnetic starter within five seconds, equipment is set to alarm state.

Water Fill Valve

Operates only in selected filtration mode. Fills OE with water to set level. Switching logic is relay type with hysteresis by water level.

Alarms

Critical Alarm

General alarm that defines state when any of following alarms is present:

Any FM valve
Circulation pump
Heat exchanger pump
UV lamp
Technical equipment room flooding

When critical alarm appears, pool is switched to "System Stop" mode. To clear alarm, identify and eliminate its cause, then reset critical alarm, which resets alarms of above systems.

Station Alarm