Step 4 - Continued Tuning
The resulting settings above can also be changed by altering the Additional Capacity (Step 3.B.) and Feed Rate, or by
changing the Decrease Threshold (Eq. 9). However, during these adjustments the following must be kept in mind:
- Minimizing Determination Wait Time allows the system to be more responsive, keeping the incremental doses smaller
- Decrease Threshold does not necessarily need to be updated when the Feed Duration is updated, but doing so will
help ensure the responses are made at appropriate levels
Additional Parameters
- Recovery Threshold
o May be used to change recovery characteristics. System will stop corrections once within this amount from
the residual target, making an “acceptable recovery”. This may be used to mitigate overshoot, or decrease
sensitivity of the system. Default set at 0.1ppm, but may be adjusted based on witnessed results, feed rates
used, and mixing turnover times.
- Crossover Target
o In high-use situations where recovery time is limited a Crossover Target may be employed. Should be set
at a residual level equal to or less than the boost potential of the incoming water, as determined by manual
analysis of typical incoming free ammonia concentrations, or set below the point at which a “dip” or decrease
in residual is typically witnessed during recovery.
- Determination Hysteresis
o The length of time the system waits after crossing a threshold during recovery (Crossover Target, Residual
Target) before checking for false positive.
- Confirmation Wait
o During recovery to a target, the residual must remain above a threshold for at least this length of time to be
considered valid. If the residual drops below the Recovery Threshold in the window, the system will resume
previous corrective actions.
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Initial Settings
Initial Settings
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