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Control Operation
If the output is continuously on for longer than the Output Time Limit, then output will deactivate.
Output Details
The details for this type of output include the output %, HOA mode or Interlock status, alarms related to this
output, flow input value, current cycle on time, total accumulated on-time, raw pulse rate output, and the current
control mode setting.
Settings
Touch the Edit icon to view or change the settings related to the relay.
Target
Enter the desired PPM set point for the product.
Pump Capacity
Enter the maximum flow rate for the metering pump
Pump Setting
Enter the stroke length setting for the metering pump, in percent
Specific Gravity
Enter the specific gravity of the product to be added.
Maximum Rate
Enter the maximum pulse rate that the metering pump is designed to accept
(10 - 2400 pulse/minute range).
Hand Output
Enter the output % desired when the output is in Hand mode
Flow Input
Select the flow meter to be used as an input for this control relay
5.3.19
Relay or Control Outputs, Target PPM Control Mode
ONLY AVAILABLE IF HVAC MODE IS ENABLED
Overview
In Target PPM control mode, the controller monitors the total volume of flow through up to two analog or digital
flow meters, and after a programmable volume has been accumulated, the relay activates for a calculated time to
achieve a target PPM level.
The user enters the target PPM, the volume of water to trigger the chemical feed, and the data necessary to calcu-
late the pump on-time required to maintain the target PPM in that volume of water.
Pump On-Time (sec.) =
Accumulator Setpoint (gal or l) x Product Level x 0.0036
Cycles x Pump Rating (gal or l/hr.) x Pump Setting (%) x Specific Gravity (g/cm3)
Pump On-Time (sec.) =
Accumulator Setpoint (m3) x Product Level x 3.6
Cycles x Pump Rating (I/hr) x Pump Setting (%) x Specific Gravity (g/cm3)
Control Operation
As flow accumulates, the controller updates a field called Accumulator Total. When this value is greater than or
equal to the value set for the Accumulator Volume, the relay activates for the calculated number of seconds, and the
accumulated total is reduced by the accumulator volume amount.
If the trigger volume is achieved again before the activation time has expired, the newly calculated on-time per
unit volume is added to the remaining on-time. If the relay state is continuously on for longer than the Output Time
Limit, then relay will deactivate.
Output Details
The details for this type of output include the relay on/off state, HOA mode or Interlock status, total accumulated
on-time, alarms related to this output, current cycle on time, remaining on-time, accumulator total, disturbance
input value (if used) and adjusted target setpoint (if disturbance input is used), cycles of concentration, relay type
and the current control mode setting.
