Daikin BPMK928B42, Service Manual

Page: 128 / 410

Si18-201 System control
Main Functions 115
3.6 Determination of Initial Frequency
3.6.1 Determination of Operation Frequency
Purpose of the
Function To control the operating frequency in order to ensure compressor reliability and optimise the
operating condition.
Outline
∆
D signals (difference between room temperature and temperature setting) from BP units are
used to determine the frequency corresponding to the capacities of the indoor units connected
to the BP units.
This function is also described in the following section.
Method of determining frequency
Method of determining frequency
The compressor operating frequency is determined in the following steps.
1. Selection of command frequency FSR
2. Selection of upper-limit frequency FMAX
3. Selection of lower-limit frequency FMIN
4. Selection of restriction frequency FSG
5. Execution of prohibit frequency skip control
6. Selection of target frequency FMK
When FSR
≥
droop buffer: copy
Individual droop function
buffer
Peak-cut control, etc.
Individual upper-limit buffers
Compressor protection
function, etc.
FMAX
FSG FSR
FMIN
Skip control FMK
Individual lower-limit buffers
4-way valve operation security
Wet protection function, etc.
Initial frequency
PI control
MIMO control
Defrost
Frequency fixed mode, etc.
(M1008)