Fuji Electric FRENIC-HVAC User Manual page 540

ON/OFF (ON/OFF control)
Setting the P gain (J510/J610/J660) to "OFF" enables ON/OFF control. If the feedback value
(PV) exceeds the threshold value "Command setting value SV + Hysteresis width (J515)," the
manipulated value (MV) switches between two positions 0% and 100%.
● Normal operation
Manipulated value J515
(MV)
ON
100%
0%
Command value (SV)
 I integral time (External PID control 1: J511, External PID control 2: J611,
External PID control 3: J661)
J511/J611/J661 specifies the integral time for the external PID processor.
- Data setting range: 0.0 to 3600.0 (s)
I (Integral) action
An operation in which the change rate of the MV (manipulated value: output frequency) is
proportional to the integral value of deviation is called I action, which outputs the MV that
integrates the deviation. Therefore, I action is effective in bringing the feedback amount close
to the commanded value. For the system whose deviation rapidly changes, however, this
action cannot make it react quickly.
The effectiveness of I action is expressed by integral time as parameter, that is
J511/J611/J661 data. The longer the integral time, the slower the response. The reaction to
the external disturbance also becomes slow. The shorter the integral time, the faster the
response. Setting too short integral time, however, makes the inverter output tend to oscillate
against the external disturbance.
● Reverse operation
J515
100%
OFF
Feedback value (PV)
0.0 means that the integral component is ineffective.
6-230
J515 J515
Manipulated value
(MV)
OFF
0%
Command value (SV)
ON
Feedback value (PV)