Carel Heos, User Manual

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22
ENG
Heos +0300078EN - rel. 1.6 - 23.11.2017
Duty setting operation (parameter c4)
Duty setting is a special function used to maintain control in emergency
situations with errors in the temperature control probes, until a service
callout is possible. In the event of a temperature probe error, Heos uses the
other probe available and adjusts the set point according to the setting of
parameter r0. In the event of errors on both probes, Heos switches to duty
setting mode. The controller is activated at regular intervals, operating for a
time equal to the value set for the duty setting parameter c4, and off for a
time equal to c5. Compressor speed is fi xed, at the value set for cI3.
Par. Description Def U.M. Min Max
cI3 Compressor capacity percentage with probe alarm 50 % 0 100
c4 Comp. on time in duty setting from probe alarm 5 min 0 100
c5 Comp. off time in duty setting from probe alarm 5 min 0 100
c4 c5
time
cl3
speed
Fig. 6.c
Important: during duty setting, the compressor protection times
are not observed.
The table below describes the possible fault situations relating to the
control probes and the function that is activated.
Type of system Control probe fault Control Parameter
1 probe Sm Sr
†
Duty setting c4
†
Duty setting c4
2 probes
†
control with Sr r0(*)
†
control with Sm r0(*)
† †
Duty setting c4
* r0 must be >0.
Multi-evaporator system control
Each evaporating unit has its own cooling capacity (parameter PE2).
Compressor speed is calculated based on the average between the
diff erence between the control temperature and the set point on each
unit, weighed according to the cooling capacity of each evaporator. If
there are three evaporators, the total error E_TOT that the P+I control
algorithm will use to calculate the output depends on the cooling
capacities of the three units (PM, PS1, PS2).
The E_TOT calculated in this way is applied to a P+I algorithm so as to
determine the required percentage of cooling capacity, which translates
into the required compressor speed.
Superheat modulation (multi-evaporator)
On showcases where active, the superheat set point varies between
the user setting (P3) and an off set (PE7) with P+I logic, so as to correctly
manage the control temperature. As the control temperature approaches
the set point, the superheat set point is increased, so as to further close
the expansion valve. To activate this function, set the off set PE7 to a value
greater than 0.
Duty setting with multi-evaporator
Activation of duty setting mode on the Master controller implies that
the compressor management times set for the Master controller are also
used by all the connected Slaves. The Slaves will activate and deactivate
control of the expansion valve according to compressor operation (ON
or OFF). If a Slave is in duty setting mode (due to a probe error), the
proportional component corresponding to the unit with the error will be
equal to the value of parameter cI3, weighted according to the cooling
capacity (PE2).
6.6 Compressor
6.6.1 Inverter compressor control
The compressor can be selected during the wizard (commissioning).
Before selecting the compressor installed on the unit, make sure that the
Power+ inverter is connected to the Heos controller. In screen Dab01,
select one of the compressors available for the application.
•
TOSHIBA DA91A1F-230V
•
TOSHIBA DA130A1F-230V
•
TOSHIBA DA220A2F-230V
•
TOSHIBA DA330A3F-230V
•
TOSHIBA DA420A3F-230V
Other models can be implemented by contacting Carel HQs directly.
The thermodynamic parameters and times are part of the Heos controller
software: these are used to control the compressor, making sure that
normal operating conditions are always within the limits set by the
manufacturer. The electrical parameters are written in the Power+ inverter
fi rmware: these are the parameters that allow the sensorless controller to
eff ectively manage the compressor. Selecting the compressor involves
confi guring all the thermodynamic parameters and times on the Heos
controller; writing the parameters (last item on the screen) initialises the
electrical parameters on Power+. Once the model has been selected and
the parameters downloaded to Power+, no other compressor parameters
are required to start the unit.
Envelope management
The envelope defi nes the operating range in which the compressor can
safely work for an indefi nite time. This can be represented graphically by
plotting several limits, inside which normal operating conditions need
to be kept. The fi gure shows the envelope for the Toshiba DA series
horizontal compressors.
Evaporation temp.
C
ondensing temp
.
Min 15 rps
CR = 2
Min 30 rps
Min 50 rps
Min
30
rps
Max Cond T 55°C
Min Cond T 10°C
M
in E
vap
T -35°C
M
ax E
vap
T 15°C
Fig. 6.d
The limits of the envelope consist of:
•
Minimum and maximum condensing temperature
•
Minimum and maximum evaporation temperature
•
Minimum and maximum compression ratio (CR)
•
Maximum compressor current draw
Normal operating conditions are defi ned by:
•
Evaporation pressure (or saturated temperature)
•
Condensing pressure (or saturated temperature)
•
Discharge temperature
•
Rotation speed (rps)
The form of the envelope may change according to compressor speed,
and with this the normal operating conditions considered as being safe
for the compressor. Consequently, a certain pair of operating pressures
may be considered safe (within the envelope) at a certain speed, and
unsafe (outside the envelope) at another speed.