Pi Control - Daikin FTX25JVEA9 Service Manual

System control
3.22

PI Control

Based on the ∆ D signal, MAX α of the command frequency is monitored every 20 seconds, and
Outline
PI control is provided accordingly. (Coefficient of PI control varies for each S value.)
At every sampling time TFSMP, the maximum value (MAX α ) of α value is calculated, and if the
P Control
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.
When the ∆ D signal does not change for the specified time, the frequency is increased or
I Control
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)
140
Si18-201
Main Functions