Daikin FTX25JVEA9, Service Manual

Page: 153 / 410

System control Si18-201
140 Main Functions
3.22 PI Control
Outline Based on the
∆
D signal, MAX
α
of the command frequency is monitored every 20 seconds, and
PI control is provided accordingly. (Coefficient of PI control varies for each S value.)
P Control At every sampling time TFSMP, the maximum value (MAX
α
) of
α
value is calculated, and if the
result differs from the previous value, the frequency is changed according to the amount of
fluctuation.
When the previous MAX
α
is MAX
α
1 and the newest MAX
α
is MAX
α
0, the upper-limit value of
MAX
α
is
MAX_ALFA_MX(9).
Operating frequency operating amount
∆
F:
∆
F = KP × (MAX
α
0 - MAX
α
1)
P control is prohibited under the following conditions
(Equation (A))
MAX_ALFA_P1(3)
≤
MAX
α
0
≤
MAX_ALFA_P2(5)
MAX_ALFA_P1(3)
≤
MAX
α
1
≤
MAX_ALFA_P2(5)
P control is prohibited under left condition.
I Control When the
∆
D signal does not change for the specified time, the frequency is increased or
decreased according to the MAX
α
value to set the MAX
α
value to the specified level.
When MAX
α
value is small
→
Frequency is decreased
When MAX
α
value is large
→
Frequency is increased
When MAX
α
at TFSMP(20) timer time-over is MAX
α
0:
If MAX
α
0
≥
MAX_ALFA_12(6)
When frequency does not change for TFSMP × M(120 sec)
Operating frequency operating amount
∆
F is set to
∆
F = KI × (MAX
α
0 - MAX_ALFA_MK(3))
If MAX
α
0
≤
MAX_ALFA_11(2)
Operating frequency is decreased at every TFSMP(20 sec)
Operating frequency operating amount
∆
F is set to
∆
F = -KI × BI(1)
I control is prohibited when MAX_ALFA_11(2) < MAX
α
0 < MAX_ALFA_12(6)