Daikin FTXB50BV1B, Service Manual

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Function & Control
19
2.14.2 Command Rotation
Cut in upon termination of Starting Control.
Achieve capacity control by controlling the compressor rotation based on:
• Temperature difference between set and room temperature, ∆ T.
• Limit Rotation.
• Defrost control.
2.14.3 Fuzzy Control
Based on temperature difference, ∆ T, current fan speed setting & current indoor operating mode at every 30
seconds interval.
Temperature Difference
Use to set target for compressor frequency change
Compressor frequency is increased or decreased
Condition 1
∆ T
Condition 2
d ∆ T
∆ T
t
= T
room
- T
set
d ∆ T
t
= ∆ T
t
- ∆ T
t-1
2.14.4 PI Control
Based on P control & I control.
P control:
∆ T of each indoor is calculated at every sampling time of 20s and compressor rotation is adjusted
according to the difference from the previously calculated rotation.
I control:
if the operating frequency is not changed more than a certain fi xed time:
• If Σ∆ T is small
:
lower frequency.
• If Σ∆ T is large
:
increase frequency.
2.14.5 Limit Rotation
Determine from
• Upper limit rotation
A minimum value was determined among the upper limits rotation, i.e. protection controls.
• Lower limit rotation
A maximum value was determined among the lower limits rotation, i.e. protection controls.
Generally, compressor rotation is controlled within 5 zones: stop, drop, keep, up and reset subjected to a
particular operating temperature/current/pressure.
Zone Control
Stop
Compressor is stopped when a certain limit reaches the stop zone for abnormality
correction.
Drop Frequency will be dropped with a timer setting.
Keep Frequency is maintained at lower/upper limit.
Up Frequency will be increased with a timer setting.
Reset Frequency lower/upper limit is canceled and returned to command rotation.