Chemtrac HydroAct HA4, User Manual

Page: 69 / 97

4.1 PID Control 69
Enabled
Enables the integral windup protection feature. Options are “Yes” or “No”.
Minimum
The smallest accumulated error the integral term is allowed to wind up, usually negative or
commonly zero. Values from -1000.00/% to +1000.00/%
Maximum The largest accumulated error that the integral term is allowed to windup, usually positive.
Values from -1000.00/% to +1000.00/%
4.1.2.4.4 Overfeed Protection Tab
Overfeed protection is designed to identify problems associated with dosing equipment. Blocked
injectors, empty day tanks and dosing pump failures are likely causes to trigger this feature. This alarm
may identify the problem before the detrimental effects of control loss are encountered. If the PID
output is judged to be having no effect then the controller will enter the specified fail mode, log the
event in the system log and sets off a control alarm. Manual intervention is required to rectify the fault
and reset the PID controller by setting the desired run mode using the PID Setup or Overview screens.
Enabled This enables overfeed protection. If enabled the parameters below are available for configu-
ration.
Timeout Time period in which the process variable must respond to dosing before overfeed protection
activates. Values in HH:MM:SS
Interval Amount the process variable must move towards setpoint to reset the timeout timer set above.
Deadband Overfeed protection is disabled when process variable is within this value of setpoint.
4.1.2.4.5 Boost Tab
Boost allows for a temporary secondary setpoint or a fixed control output. This can be used for shock
dosing of a swimming pool or periodic increased dosing for additional disinfection of a bottle plant
washer. When activated the boost function will either change the PID setpoint to the secondary value
(usually higher) or set the control output to the selected level and will maintain it for a pre-determined
time. It will then disable the function for a configurable period to prevent overuse.