Fuji Electric FRENIC-HVAC User Manual page 543

4) Suppressing oscillation whose period is approximately the same as the time specified by
function code J512/J612/J662 (Differential time)
Decrease that of J512/J612/J662 (Differential time).
Decrease the data of function code J510/J610/J660 (Gain), if the oscillation cannot be
suppressed even though the differential time is set at 0 sec.
 Feedback filter (External PID control 1: J513, External PID control 2: J613),
External PID control 3: J663)
J513/J613/J663 specifies the time constant of the filter for feedback signals under the external
PID control.
- Data setting range: 0.0 to 900.0 (s)
- This setting is used to stabilize the PID control loop. Setting too long a time constant makes
the system response slow.
J514 External PID Control 1 (Anti-reset wind-up)
J514, J614 or J664 suppresses overshoot under external PID control 1, 2 or 3 using an
external PID processor, respectively. As long as the deviation between the PID command and
its feedback is out of the preset range, the integrator holds its value and does not perform
integration operation.
- Data setting range: OFF, 0.01 to 9990.00 (The setting range is restricted by the maximum
scale and minimum scale.)
6.3 Details of Function Codes
J614 (External PID Control 2 (Anti-reset wind-up))
J664 (External PID Control 3 (Anti-reset wind-up))
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