1592020670 XRi77CX-CH GB r1.1 15.10.2019
XRi77CX-CH
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3.4.10
REGULATION OUTPUT
If
oAx=inV
, the related output will work as regulation output and will stay active as soon as the
regulation request is running.
4.
PULL DOWN
An automatic function named PULL-DOWN is implemented. This function forces the controller to work
at
PMA
until reaching a specific SETPOINT (par.
CCS
) for a maximum interval of time (par.
CCt
). The
PULL-DOWN function is activated:
At start-up if the temperature measured from the regulation probe is higher than the SETPOINT
After any defrost
If the temperature measured from regulation probe go over the
SET+HY+HY1+oHt
value.
If one of the above conditions happens, the controller will maintain the maximum compressor speed
(
PMA
) until reaching the
CCS
setpoint. The maximum interval of time for any PULLDOWN is defined
from par.
CCt
.
5.
EVAPORATOR FAN CONTROL
The evaporator fan control mode is selected by means of the
FnC
parameter:
-
FnC = C_n:
fans will switch ON and OFF with the compressor and
not run
during defrost
-
FnC = o_n:
fans will run even if the compressor is off, and not run during defrost
After defrost, there is a timed fan delay allowing for drip time, set by means of the
Fnd
parameter.
-
FnC = C_Y:
fans will switch ON and OFF with the compressor and
run
during defrost
-
FnC = o_Y:
fans will run continuously also during defrost
The par.
FAP
is used to select which temperature probe will be used from the evaporator fan regulator.
A specific setpoint (par.
FSt
) provides the temperature value, detected by the evaporator probe, above
which the fans are always OFF. This is used to make sure circulation of air only if his temperature is
lower than set in
FSt-HYF
.
5.1
FORCED ACTIVATION FOR FANS
This function, managed by the
FCt
parameter, is designed to avoid short cycles of fans, that could
happen when the controller is switched on or after a defrost, when the room air warms the evaporator.
If the difference between the evaporator temperature and the room temperature is higher than the
FCt
value, the controller will activate the fans. This function is disabled if
FCt=0
.
5.2
CYCLIC ACTIVATION OF THE FANS WHEN THE COMPRESSOR IS
SWITCHED OFF
When
FnC=C-n
or
C-Y
(fans in parallel to the compressor), the fans will be able to carry out on and
off cycles even if the compressor is switched off. The on and off interval of time follow the
Fon
and
FoF
parameters. When the compressor is stopped, the fans will go on working for the
Fon
time. On
the other side, with
Fon=0
the fans will stay always off when the compressor is off.
6.
CONDENSER FAN CONTROL
The condenser fan control mode is selected by means of the
FCC
parameter:
-
FCC = C_n:
fans will switch ON and OFF with the compressor and
not run
during defrost
-
FCC = o_n:
fans will run even if the compressor is off, and not run during defrost
-
FCC = C_Y:
fans will switch ON and OFF with the compressor and
run
during defrost
-
FCC = o_Y:
fans will run continuously also during defrost
The par.
FAC
is used to select which temperature probe will be used from the condenser fan regulator.
This regulator uses a specific setpoint (par.
St2
) and differential (par.
HY2
) to activate and deactivate
the condenser fans:
-
If
T>St2+HY2
the condenser fans are activated
-
If
T<St2
the condenser fans are deactivated
The par.
FCo
can be used to keep the ventilators active for a period after compressor OFF.
7.
AUXILIARY REGULATOR
The auxiliary regulator can be be linked to a digital output (relay) for ONOFF regulation.
The parameters used to configure the auxiliary regulators are the following:
ACH
Kind of action for auxiliary regulator
SAA
Set point for auxiliary regulator
SHY
Differential for auxiliary regulator
ArP
Probe selection for auxiliary regulator
Sdd
Auxiliary regulator disabled during any defrost
8.
DUAL MAP FEATURE
The controller is programmed with 2 different parameter maps. In this way, it is possible to choose the
right map to meet both LT and NT applications. There are two different way to do this:
-
If
i1F=nt
, it will be possible to change the working map by using the digital input.
-
By using the
DOWN
button, if it is linked to the map changing function. If so, keep it pressed 3
sec to activate the relative function.
9.
VARIABLE SPEED COMPRESSOR CONTROL
9.1
FREQUENCY MODE
The controller can drive variable speed compressors with frequency control input. The frequency
output port can issue a frequency signal from 30 to 200Hz, duty cycle=50%. A special cable must be
used in order to connect the frequency output of the controller to the frequency input of the specific
inverter.
-
CAB/EM1: cable
DD900002 20
for Embraco VNEK/U models
-
CAB/SE1: cable
DD900002 22
for SECOP NLV models
NOTE:
-
An inverter compressor can be completely controlled from the frequency output only.
-
Only one compressor can be connected when frequency mode is used
9.2
PARAMETERS
The following parameters are used to set the regulation:
HY1
Differential for proportional regulation:
(0.1 to 25.5°C; 1 to 45°F)
Fr0
Frequency output value with compressor stopped:
(0 to 50Hz) frequency output
signal when compressor stopped
PMi
Minimum compressor speed (in percentage):
(0 to PMA)
PMA
Maximum compressor speed (in percentage):
(PMi to 100%)
voS
Signal output variation (increment) when temperature is increasing:
if
vdC=FrE
then 1 to 100 Hz, otherwise 10 to 1000 rpm
vo2
Signal output variation (decrement) when temperature is decreasing:
if
vdC=FrE
then 1 to 100 Hz, otherwise 10 to 1000 rpm
vo3
Signal output variation (decrement) after any Pull Down:
if
vdC=FrE
then 1 to 100
Hz, otherwise 10 to 1000 rpm
t1F
Time with compressor at PMI before stopping regulation:
(0 to 999 min)
SPi
Compressor speed (in percentage) in case of any error probe:
(PMi to PMA)
CMn
Continuous mode during Normal Mode:
(n; Y)
CME
Continuous mode during Energy Saving Mode:
(n; Y)
The value of the par
HY1
can normally be set to the same value of par.
HY
. In this way, the regulation
band will be extended from
SET
to
SET+HY+HY1
. The device will activate the regulation when the
measured temperature will go over the
SET+HY
value and will stop the regulation when the
temperature will reach the
SET
value. When the regulation is running, the frequency output, and then
the compressor speed, will be calculated in proportional way by using the
PM
i…PMA
band. After
reaching the
SET+HY
value, the controller will start increasing the frequency output, and then the
equivalent compressor speed, by using the par.
voS
. The speed increasing will be stopped as soon
as the proportional calculated value (for the compressor speed) hooks the requested value. In case of
temperature decrement and compressor speed higher than the new requested value, the controller will
decrease the compressor speed proportionally by using the
vo2
value. After any Pull Down, and in
case of continuous mode regulation (
CMn
or
CME=Y
) it is possible to speed up the compressor speed
decrement by using par.
vo3
. This helps to avoid subfreezing conditions due to high compressor speed
after reaching the regulation setpoint.
After reaching the
SET
value it is possible to force the compressor speed to
Pmi
for
t1F
min.
In case of any regulation probe error, the compressor speed will be set to the value of par.
SPi
.
It is possible to enable a cyclic or a continuous mode operation both during normal mode or energy
saving mode:
-
CMn, CME = Y
: after reaching the SETPOINT the VSC will keep on running
-
CMn, CME = n
: after reaching the SETPOINT the VSC will be stopped (after
t1F
)
9.3
TEMPERATURE DEADLOCK CONTROL
The controller can detect temperature deadlocks. If the actual speed is not able to reach the
SETPOINT, and if this condition persists for a long interval of time, then the controller will increment
the actual speed until reaching the SETPOINT. A differential (par.
th1
) and a speed increment (par.
oFS
) is used to detect and manage any deadlock condition.
9.4
HOT GAS DEFROST
In case of using hot-gas defrost, it will be possible to set the compressor speed by using par.
Aod
.
9.5
PULL DOWN
An automatic function named PULL DOWN is implemented. This function forces the controller to work
at
PMA
until reaching a specific SETPOINT (par.
CCS
) for a maximum interval of time (par.
CCt
). The
PULL-DOWN function is activated:
-
At start-up if the temperature measured from the regulation probe is higher than the
SET+HY+HY1
-
After any defrost
-
If the temperature measured from regulation probe go over the
SET+HY+HY1+oHt
value.
If one of the above conditions happens, the controller will maintain the maximum compressor speed
(
PMA
) until reaching the
CCS
setpoint. The maximum interval of time for any PULLDOWN is defined
from par.
CCt
. At the end of any PULL DOWN it is possible to set an interval of time (par.
t1F
) with
predefined compressor speed (
PMi
).
9.6
OIL MIGRATION CONTROL (VALID ONLY FOR VSC)
To avoid oil migration during variable speed compressor operation, a lubrication control is
implemented. If the compressor works with a speed lower than the
MnP
threshold for
tMi
time, then
the compressor speed will be increased to
PMA
for
tMA
time.
NOTES:
-
MnP= PMi to PMA, nu, OFF
-
If
MnP=nu
, then this function is disabled
If
MnP=oFF
, then the compressor will be stopped for
tMA
if it works continuously for
tMi
9.7
STEP REGULATION: VSD AND ONOFF COMPRESSOR
The following parameters are used to set up the step regulation function:
Pon
Step regulation: inverter compressor speed during ton (in percentage)
SCd
Step regulation: deactivation of the ONOFF compressor
ton
Step regulation: delay before activation of the second compressor (when T> SET + HY + HY1)
toF
Step regulation: delay before deactivation of the second compressor
don
Step regulation: minimum operating time of the second compressor
doF
Step regulation: minimum stop time of the second compressor
The step regulation is activated when at least one ONOFF compressor is enabled (
oAx=CP1
or
CP2
)
and
oAn=FrE
.
The second compressor (the ONOFF one) will be activated when T > SET+HY+HY1.
The ONOFF compressor deactivation follows par.
SCd
.
