PI v2

Requires dwOption-05, Process Control.

A useful control-loop component for a variety of closed-loop systems.

Produces a clamped output that reacts to the error between the feedback and setpoint inputs, with the sum of parallel proportional and integral process terms.

The output clamp also clamps the integral term to avoid saturation of that term.

The integral term's input is clamped to limit saturation from large, transient input errors.

• Available only in the dw2xx & dw2xx-v2 series products
• Requires library: Process Control (option -05) or Basic Functions
• Firmware versions 0x2024 and later

PI v2 - Setpoint

The closed-loop system's desired setpoint. The system's feedback signal is subtracted from the setpoint to produce the error term.

PI v2 - Feedback

The closed-loop system's feedback signal. It is subtracted from the setpoint to produce the error term.

PI v2 - Integral Preset Value

The integral term is immediately set to this value while Integral Preset Enable is active.

PI v2 - Proportional Gain

The input error is multiplied by this value to produce the proportional term.

Larger proportional gains produce stronger responses. Too large a value can lead to system instability in the form of vibration or violent jerking.

When the proportional gain is too small, system instability is characterized by slower hunting around the setpoint, possibly including large swings.

PI v2 - Integral Time

The time in which the integral term will change by 100% in response to a 100% error input.

Smaller integral times produce faster responses. Too short an integral time can lead to system instability in the form of vibration or violent jerking.

When the integral time is too long, system instability is characterized by slower hunting around the setpoint, possibly including large swings.

PI v2 - Integral Preset Enable

The integral term is immediately set to the integral preset value while this parameter is active.

PI v2 - PI Enable

Both the function block's output, and the integral term are immediately reset to 0.00% while this parameter is inactive.

PI v2 - Lower Clamp

Both the function block output and the integral term can not be less than this value.

When the output equals this number, the integral term is held at its current value.

PI v2 - Upper Clamp

Both the function block output and the integral term can not be greater than this value.

When the output equals this number, the integral term is held at its current value.

PI v2 - Output

The function block output is used to provide negative feedback in a closed-loop system.

The output is typically connected to the Trim Input of a Trim function block, found in the Control function block group listing.

PI v2 - Error

Feedback input is subtracted from Setpoint to produce the input Error.

PI v2 - Proportional Term

The Error is multiplied by Proportional Gain to produce the Proportional Term.

PI v2 - Integral Term

The Error is clamped and then continuously integrated according to the Integral Time to produce the Integral Term

Integrator hold

PI v2 - Clamp Monitor

Active when the function block output is equal to the upper or lower clamp value.

The Integral Term is held at its current value while the clamp is active.

PI v2 - Integral Error Clamp

Places a symmetrical clamp around the function block input Error prior to passing the error to the integrator. This prevents saturation of the integral term that may be caused by large, transient input errors.

PI v2 - Integral Enable

The integral term is immediately reset to 0.00% while this parameter is inactive.

PI v2 - Integral Hold

The integral term is held at its current value while this parameter is active.