EVCO EPU2LXP1CH Installer manual - Manual (Page 58)

EVCO S.p.A. c-pro 3 micro CHIL | Application manual ver. 1.0 | Codice 144CP3CHE104
page 58 of 120
8.6.3 Auto adaptive control
If the CHW leaving temperature still remains outside the zero energy band, even after the extra-time interval set in parameter PC17
has elapsed, the switching ON or OFF of a further power step will be requested.
The setting of parameter PC18 = 1 activates an output-temperature auto-adaptive control function, in which the zero energy band is
calculated in such a way as to take into account the dynamic properties of the plant and load variations. In particular, the zero energy
band can vary taking into account compressor timings and the number of start-ups per hour. In this case, the value of parameter PC14
(zero energy band) only makes sense at unit start-up, whereas it will be recalculated – within the minimum PC15 limit and maximum
PC16 limit – to “adapt” to an intermediate operating situation, as compared with the maximum number of hourly start-ups (parameter
PC09).
PC09 = maximum number of hourly start-ups
PC14 = Zero energy band
PC15 = minimum limit
PC16 = maximum limit
PC17 = Extra time for out-of-zone request
PC18 = enable auto-adaptive control
Note: In the case of a twin-circuit system (PG01=2), control is carried out on the average value of the two chilled water leaving-
temperature sensors.
If one sensor fails, the control function is based on the other healthy sensor.
If both sensors fail, controlling is no longer possible. Parameter PC10 defines the number of compressors which will be activated in each
circuit.
8.7 Compressor Management
The program is capable of managing up to a maximum of 3 compressors of the same power for each circuit, thus 6 compressors in
total. Each compressor has a digital input for protection devices and a digital output for ON/OFF switching.
Compressors are controlled by lateral-band or zero energy band control (see previous chapter) with respect to the compressor timings.
8.7.1 Compressor status
The status of each compressor is visualized in the operator HMI. A compressor can take on the following statuses:
Disabled: The compressor has not been configured, the display shows “-”.
On: The status display shows “ON”.
Waiting to switch ON: The compressor is waiting for protection timings, before switching ON. The status display shows “WON”.
Off: The status display shows “OFF”.
Waiting to switch OFF: The compressor is waiting for protection timings, before switching OFF. The status display shows “WOFF”.
Alarm: The compressor is in alarm status. The status display shows “ALARM”.
Manual: The compressor is in manual operating mode. The status display shows “MANUAL”.
In the maintenance operator menu, via parameters PM01, PM02, PM03 and PM04, it is possible to read the number of operating hours
of the corresponding compressors. To zero these hours, it is sufficient to enter a “0” value using the ENTER key.
8.7.2 Rotation of compressors
Rotation of compressors is a procedure which enables balancing – as far as possible – of the number of operating hours and start-ups
of each compressor.
In case of twin circuits, rotation must balance the operation hours of both circuits. Rotation does not affect any compressors in alarm
status or manual operation mode, and is capable of dynamically switching ON other compressors, in case one or more of them should
be in alarm status.
Via parameter PC01, the program is capable of managing 4 types of rotation: FIFO, LIFO, FIFO + number of hours, LIFO + number of
hours.
1. FIFO
This method follows the “First In First Out” logic, i.e. the first compressor to be switched on will have to be the first to be switched OFF
again. This operating logic could initially lead to a great difference in the number of operating hours between the various compressors,
but, after the initial phase, the hours should more or less equalize.
This type of rotation has a peculiarity in cases where not all configured compressors within the plant are switched ON; indeed, if for
example the first compressor is switched ON and then OFF again, the next compressor to be switched ON will be the second one. The