Fujitsu WGYA050DG6 Design & Technical Manual page 161

Flow control
LINE FUNCTION
3720 Switching integral
3723 Locking time
Switching integral
The temperature-time integral is a continuous
summation of the temperature differential over time.
In this case, the decisive criterion is the difference
by which the temperature lies above or below the
common flow temperature setpoint.
The temperature-time integral gives consideration
not only to the period of time, but also to the extent
of over-/undershoot. This means that when the
crossing is significant, the supplementary source is
released earlier, or locked earlier, than with minor
crossings.
QX2
QX3
TVx Actual value of flow temperature
TVw Flow temperature setpoint
+ Int Surplus integral
- Int Deficit integral
t1 Overrun time (not completed)
t2 Overrun time (fully completed)
QX2 Release output QX2
QX3 Control QX3
- (CS01 - 45) - - (CS01 - 45) -
Control system