power failure. This alarm will be active for 1 minute following a power cycle to a CCB.
Online Help
Context sensitive help text is available on most screens by selecting the Help (?) key on the Screen Navigation bar. When the ‘help’ text is displayed, the Help key text will be backlit in green. The screenshot below shows help text displayed on System Overview screen.
System Settings Screens
The System Settings Screens are accessible through the Screen Navigation bar if the user is logged in with a sufficient security level. The variables on these screens are selected by pressing the numeric entry box, and changed by using the pop-up numeric touch pad followed by enter (↵) key. All settings are organized by system function which are selected using the tab buttons at the top of each setting screen.
Settings are organized by Bank, Wiper (optional), Flow, UV Transmittance, UV Intensity, Dose, General and Channel
categories. Online help is available for each of the plant maintenance settings that can be accessed.
Bank Settings
The following settings are available on the Bank Settings screen:
Multiple Lamp Failure SP Setpoint for the number of lamps that must fail in a bank before it is considered to have a major alarm condition and will trigger the Multiple Lamp Failure alarm.
Banks with this condition will be timed off and another bank will be operated in it’s place if there is an available healthy bank.
Multiple Ballast Failure SP Setpoint for the number of ballasts that must fail in a bank before it is considered to have a major alarm condition and will trigger the Multiple Ballast Failure alarm.
Banks with this condition will be timed off and another bank will be operated in it’s place if there is an available healthy bank.
Min. Banks On / Channel Setpoint for the minimum number of banks in a channel that will always be requested to run by the dose pacing routine, regardless of current process
conditions. If this value is set to 0, then all banks in a channel may be shut off if there is a Low Flow alarm condition.
Auto Bank Sorting Determines whether an automatic rotation of the lead bank will occur when the current lead bank’s lamp life reaches the End of Lamp Life hours setpoint.
Sort Last Bank in Channel Determines
whether the last lag bank in each channel will be sorted when an automatic rotation occurs. This is used to permanently assign a desired bank to a lag or standby position.
Wiper Settings
Wiper Sequence Cycle Time Determines the time between automatically schedule wipe sequences. When an automatic wipe sequence occurs, all wiper groups on a HSC will be
requested to wipe one at a time if they are not in an alarm condition.
Flow Limit for Wiping Determines the flow percentage of the peak channel flow that can be reached before automatic wiping is disabled.
Flow Settings
Flow Signal Sample Rate Determines the frequency at which the total flow on the
Flowmeter analog input is measured. This value should be increased if there is a very noisy plant flow signal that cannot be dampened by using the Flow Signal Filter Factor.
Flow Signal Filter Factor Used to set the proportion of the currently sampled flow signal that is averaged with the historically saved flow value in order to determine the current flow value. An entered value of 0.5 represent 50% of the current flow averaged with 50% of the stored flow. In order to dampen out a noisy plant flow signal, this value should be reduced in 0.1 increments.
Low Flow Alarm Setpoint Determines the setpoint that the currently measured flow must drop below in order to initiate a Low Flow alarm timer.
Low Flow Alarm Delay Determines the setpoint for the Low Flow alarm timer.
Flowmeter Full Scale Used to enter the value in engineering units at which the plant flow meter is outputting 20mA. This represents the full scale of the Flowmeter signal.
Flowmeter Default Value Determines the flow value that is used for dose pacing if there is a Flowmeter signal fault, or if the source of signal input for flow is set to manual.
UVT (Transmittance) Settings
UVT Signal Sample Rate Determines the frequency at which the UV Transmittance signal analog input is measured. This value should be increased if there is a very noisy plant UVT signal that cannot be dampened by using the UVT Signal Filter Factor.
UVT Signal Filter Factor Used to set the proportion of the currently sampled UV
Transmittance signal that is averaged with the historically saved UVT value in order to determine the current UVT value. An entered value of 0.5 represent 50% of the current UVT averaged with 50% of the stored UVT. In order to dampen out a noisy plant UVT signal, this value should be reduced in 0.1 increments.
Low UVT Alarm Setpoint Determines the setpoint that the currently measured UV Transmittance must drop below in order to initiate a Low UVT alarm timer.
Low UVT Alarm Delay Determines the setpoint for the Low UV Transmittance alarm timer.
UVT Default Value Determines the UV
Transmittance value that is used for dose pacing if there is a UVT signal fault, or if the source of signal input for UVT is set to manual.
UVT Manual / Online Used to toggle the source of the UV Transmittance signal between a manually entered value and a measured analog value.
UVI (Intensity) Settings
Low Intensity Alarm SP Determines the setpoint in percentage below which a Low Intensity alarm will be generated for a particular bank. The currently measured analog intensity signal current is compared against the predicted signal current at the present UV Transmittance and lamp output conditions in order to calculate a percentage value that is compared against the alarm limit.
Dose Settings
UV Dose Alarm Offset Determines the percentage setpoint below which a Low UV Dose alarm will be generated. The currently calculated dose value is compared against the configured Design Dose Setpoint in order to calculate a percentage value which is compared against the alarm setpoint.
Design Dose Setpoint Determines the setpoint for UV Dose control of the Dose Pacing routine.
The Dose Pacing routine will modulate bank power level and bring banks and channel in and out of operation as required in order to maintain the dose a value just above this setpoint.
Dampen Timer Preset Determines the amount of time that the Dose Pacing routine must be calling for a bank’s power level to be reduced before a lower power level will be used. This feature is used to minimize bank power cycling.
Bank Time Off Delay Determines the amount of time that the Dose Pacing routine must be calling for a bank to be turned off before it will be
allowed to deenergize. While this timer is running, a bank will typically be operated at minimum power. This feature is used to minimize bank on/off cycling.
General Settings
Minor Alarm Delay Determines the setpoint for the alarm delay for minor alarms.
Major Alarm Delay Determines the setpoint for the alarm delay for major alarms.
Critical Alarm Delay Determines the setpoint for the alarm delay for critical alarms.
Winterization Mode Used to toggle the Winterization Mode selector between Enabled and Disabled. When this option is enabled, all operator interface and SCADA alarms are cleared. This option is used to mask nuisance alarms during seasonal equipment shutdown periods.
Operator Control Security Used to toggle the Operator Control Security mode selector between Enabled and Disabled. When this option is enabled, the operator must log in to be able to change any system modes or enter any values on the operator interface. The default operator Username is OP and Password is 11111. After ½ hour of inactivity, the currently entered Username and Password is cleared and must be reentered to continue operating the system. This option is used to prevent
unauthorized changes to system operating parameters.
Channel Settings
Unless the system is configured as a multi-channel control system, all Channel Settings will not appear, except for the Hydraulic Max setting.
Hydraulic Max Represents the peak flow (in engineering units) that a channel can pass before a Hydraulic Max alarm will be generated.
This value is also used to allow uneven flow splitting on multi-channel systems. Normally the Hydraulic Max value is set to the same value for each channel and the flow through each open channel is assumed to be the total flow divided by the number of open channels. These values may be set differently for uneven flow splitting, in which case the flow through a channel is equal to the total flow times the Hydraulic Max for that channel divided by the total Hydraulic Max for all channels.
Inlet Gate Travel Time (N/A) Represents the maximum time required for the inlet slide gate to complete its travel from a fully open or closed position. This setpoint is used to determine how long to wait when a gate is commanded to move before checking for alarm conditions.
Channel Fill Delay Represents the amount of time that will pass after an inlet slide gate is commanded to open before a Channel Low Level alarm condition will be set. When an operating channel is in a Low Level alarm
condition, it is not considered healthy and available to the Dose Pacing routine.
Min No. of Channels On (N/A) Represents the minimum number of channels that will be open and operating regardless of the current system flow. This value must always be equal to or greater than 1.
Channel Closing Delay Determines the amount of time that the Dose Pacing routine must be calling for a channel to close before it is taken out of operation.
Channel Time off Delay Determines how much time banks in a closed channel will continue to time off before they are requested to shut down.
This feature allows disinfection to continue in a channel that has been taken out of operation, until all effluent has had a chance to drain down past the UV banks.
Channel Flow Limit (N/A) Determines the flow setpoint at which an additional channel will be called to open. This value should be set to the minimum flow that a channel will be able to disinfect at the lowest UV Transmittance value that a plant will experience and is typically set to the plant design peak flow divided by the total number of configured channels.