37 | P a g e
Figure 19 – Digital Constant Pressure Diagram
SIMPLE MODE Control
Phase Technologies has developed a proprietary controller which involves fewer
parameters to tune constant pressure performance. When the PROPORTIONAL GAIN
parameter is set at the lowest value, the display will read "SIMPLE MODE". In SIMPLE
MODE a set of control equations is used which may not require the user to tune the system
to obtain acceptable performance.
A well-tuned PI controller will result in smoother pressure control but may not be required.
When the controller is in simple mode the only parameters which affect the pressure control
loop are the psi SETPOINT, STARTUP RAMP, SHUTDOWN RAMP and BOOST
AMOUNT, which function in the same way as they do in the PI control mode. Adjusting
ramp times may smooth out any oscillation or overshoot in simple mode. If pressure is not
adequately controlled, switch to PI control by increasing parameter PROPORTIONAL
GAIN.
Using PI Control in Constant Pressure
When using an analog pressure transducer for control in constant pressure water systems,
it may be desirable to use a proportional-integral (PI) controller in the feedback loop. This
type of controller has a proportional gain and integral gain which can be tuned by the user
to obtain optimum performance for each particular application. Increase parameter
PROPORTIONAL GAIN to switch control from Simple Mode to PI control. It is
recommended to start with a parameter value of 5. A proportional gain value too low will
result in slow response time to reach the psi setpoint. A value too high will result in
overshoot of the psi setpoint and may create excessive oscillation of pressure.
CAUTION: Operating the system in
MANUAL mode on the keypad overrides
signals from the pressures switches.
Operating the system in this mode may
lead to dangerous pressures in closed
plumbing systems
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