1592023220 XM660K_XM670K GB r5.4 2021.09.01
XM660K - XM670K
4/9
Display
Causes
Notes
OTHERS
EE
EEPROM serious problem.
Output OFF.
Err
Error with upload/download parameters.
Repeat the operation.
End
Parameters have been correctly
transferred.
dEF
Defrost is progress
cLn
Cleaning function active
11.1
ALLARM RECOVERY
Probe alarms
P1
,
P2,
P3
and
P4
start some seconds after the fault in the related probe; they automatically
stop some seconds after the probe restarts normal operation. Check connections before replacing the
probe.
Temperature alarms
HA
,
LA,
HA2
and
LA2
automatically stop as soon as the temperature returns to
normal values.
Alarms
EA
and
CA
(with
i1F
=
bAL
)
recover as soon as the digital input is disabled. Alarm
CA
(with
i1F
=
PAL
) recovers only by
switching off and on
the instrument.
12.
CONTROLLING LOADS
12.1
TEMPERATURE PROBE REFERENCE FOR REGULATION
Up to 5 temperature probe can be used for the temperature regulation.
It’s possible to set the probes used for temperature regulation. Up to
4 Temperature inputs Pb1, Pb2, Pb3,
Pb4, can be used. To support above function, the parameters rPA, rPb, rP3, rP4, are used.
Which temperature probe methods of combine is set by par. rPd among the following: Average, Minimum,
Maximum, First, or Mix.
rPd = rPA:
temperature detected by the probe set in the parameter rPA
rPd = rAb:
mix between rPA and rPb defined by rPE parameter
rPd = AUr:
average temperature of all the probes defined as Regulation Probe in the parameters rPA,
rPb, rP3, rP4
rPd = LoE
: minimum value among all the temperature probes defined as Regulation Probe in the
parameters rPA, rPb, rP3, rP4
rPd = HiE:
maximum value among all the temperature probes defined as Regulation Probe in the
parameters rPA, rPb, rP3, rP4
12.1.1
Sensors failure
In case of multiple temperature sensor regulation: (rPd = rAb, Aur, LoE, HiE), and with sensor failure, the
remaining sensors are used for the regulation.
In case of all sensor failure, the regulation will be performed according to Con and COF parameters
12.2
DUAL TEMP MODE OPERATION
Controller can have up to 4 pre-set regulation.
The preset regulation is set in the parameter MAP.
By digital input or supervising system is possible to enable the second regulation mode, set in the
parameter MP1.
In this way a dual temp case can be easily set and controlled.
12.2.1 Second map function by digital input configuration
By setting on digital input among i1F, i2F, i3F as the “nt” the map set in the parameter
MP1is loaded when
the digital input is enabled.
12.3
THE SOLENOID VALVE
The regulation is performed according to the temperature measured by the thermostat probe that can be
physical probe or virtual probe obtained by a weighted average between two probes (see parameters
table description) with a positive differential from the set point. If the temperature increases and reaches
set point plus differential the solenoid valve is opened and then it is closed when the temperature reaches
the set point value again.
In case of fault in the thermostat probe the opening and closing time of solenoid valve is configured by
“
Con
” and “
CoF
” parameters.
12.4
PUMP DOWN BEFORE DEFROST
The following parameters has been added:
Pdt
pump down type (nu; FAn; F-C)
With
Pdt = nu,
the pump down is not enabled.
With
Pdt = Fan
, when a defrost trigger is given:
a.
Compressor relay will be open.
b.
EEV valve (if present):
i.
will be closed with CrE = n, y
ii.
will be open with CrE =EUP or EU5
c.
Fan will be forced on for Pdn time
With
Pdt = F-C,
when a defrost trigger is given:
a.
EEV valve (if present):
i.
will be closed with CrE = n, y
ii.
will be open with CrE =EUP or EU5
b.
Compressor relay and Fan will be forced on for Pdn time
Pdn
pump down duration (0 to 255 min)
12.5
DEFROST
Defrost starting
In any case, the device check the temperature read by configured defrost probe before starting
defrost procedure, after that:
-
(If RTC is present)Two
defrost modes are available through the “
tdF
” parameter: defrost with electrical
heater and hot gas defrost. The defrost interval is controlled
by parameter “
EdF
”: (EdF = rtc) defrost is
made in real time depending on the hours set in the parameters
Ld1..Ld6
in workdays and in
Sd1…Sd
6
on
holidays; (EdF = in) the defrost is made every “
IdF
” time;
-
defrost cycle starting can be operated locally (manual activation by means of the keyboard or digital
input or end of interval time) or the command can come from the Master defrost unit of the LAN. In this
case the controller will operate the defrost cycle following the parameters it has programmed but, at
the end of the drip time, will wait that all the other controllers of the LAN finish their defrost cycle before
to re-start the normal regulation of the temperature according to
dEM
parameter;
-
Every time any of the controller of the LAN begin a defrost cycle it issue the command into the network
making all the other controllers start their own cycle. This allows a perfect synchronisation of the defrost
in the whole multiplexed cabinet according to
LMd
parameter;
-
Selecting
dPA
and
dPb
probes and by changing the
dtP
and
ddP
parameters the defrost can be started
when the difference between dPA and dPb probes is lower than dtP for all ddP time. This is useful to
start defrost when a low thermal exchange is detected. If
ddP=0
this function is disabled;
Minimum defrost time
The “
ndt
” (0÷MnF) Minimum Defrost Time, set the minimum defrost duration, when the defrost is ended
by evaporator temperature probe.
The
ndt
time is taken in account everytime the defrost is trigged, independently form the value of end
defrost temperature probe and end defrost digital input status.
Defrost ending
-
When defrost is started via rtc, the maximum duration of defrost is obtained from
Md
parameter and
the defrost end temperature is obtained from
dtE
parameter (and
dtS
if two defrost probes are
selected).
-
If
dPA
and
dPb
are present and
d2P=y
the instrument stops the defrost procedure when
dPA
is higher
than
dtE
temperature and
dPb
is higher than
dtS
temperature;
At the end of defrost the drip time is controlled through the “
Fdt
” parameter.
12.5.1
Kind of defrost
The kind of defrost is set by parameter tdF among the following possibilities
tdF = Air
:
natural defrost
. Defrost is made by opening the compressor/solenoid relay. The fan during
defrost depends on the parameter Fnc. Defrost relay is off. The valve is closed
tdF = EL: defrost with electrical heater
: Defrost is made by opening the compressor/solenoid relay.
The fan during defrost depends on the parameter Fnc. Defrost relay is on. The valve is
closed
tdF = in: hot gas defrost
. Defrost is made by closing the compressor/solenoid relay. The fan during
defrost depends on the parameter Fnc. Defrost relay is on. The valve opening percentage
during the defrost is set by the par. oPd.
12.6
ON DEMAND DEFROST
Description
Controller can perform on demand defrost. It is based on the behavior of evaporator temperature.
Controller monitors the evaporator temperature and triggers a defrost if some conditions are satisfied. For
defrost efficiency its’ important to place the “end defrost probe”, usually P2, in the coldest place of the
evaporator, usually immediately after the expansion valve.
***NOTE
: Because of different type of evaporators and consequentially behaviors, it’s warmed suggested
to test and validate this algorithm in a climatic chamber before applying it in the field.
Parameters & settings:
The «On Demand Defrost» can be activated with the following settings:
CrE=”n” , EdF=”Aut”
cdt: evaporator temperature differential to trigger a defrost
(default cdt = 4°K)
nbd
:
minimum compressor run before automatic defrost
(or minimum time of activation of solenoid
valve) it has to be set properly. It prevents defrost from starting (default nbd = 4.0h)
Mbd
:
max compressor run before automatic defrost
(or max time of activation of solenoid valve): it
has to be set properly. If reached a defrost is triggered (default Mbd = 16.0h)
nct
:
minimum evap. temperature
, it has to be set properly. a defrost is triggered when this
temperature reached (default nct = -30°C)
NOTE
: with CrE=
”y” or CrE=”EUP” or CrE=EU5 only «RTC defrost» and «interval defrost» are allowed.
With EdF=”Aut” & CrE=”y” or CrE=”EUP” or CrE=EU5 the «interval defrost» will be performed, as with
EdF = in
Exceptions
:
1.
A defrost cannot be triggered if the compressor has not ran more than minimum time (
nbd
parameter
) since the last defrost or initial power up. (Resolution hh.m)
2.
If the compressor has ran for more than maximum time since the last defrost or initial power up
(
Mbd
parameter
), a defrost is triggered regardless of coil temperature .
3.
If the coil temperature reaches very low temperature, (
nct
parameter
), a defrost is triggered
regardless of
cdt
value.
12.7
FANS
CONTROL WITH RELAY
The fan control mode is selected by means of the “
FnC
” parameter:
C-n
= running with the solenoid valve, OFF during the defrost;
C-y
= running with th1e solenoid valve, ON during the defrost;
O-n
= continuous mode, OFF during the defrost;
O-y
= continuous mode, ON during the defrost;
An additional parameter “
FSt
” provides the setting of temperature, detected by the evaporator probe,
above which the fans are always OFF. This can be used to make sure circulation of air only if his
temperature i
s lower than set in “
FSt
”.
CONTROL WITH ANALOG OUTPUT (if present)
The regulation probe is set in the parameter
FAP
The modulating output (
trA=rEG
) works in
proportional way (excluding the first
AMt
seconds where the fans speed is the
maximum). The regulation set point is relative
to regulation set point and is indicated by
ASr,
the proportional band is always located above
SET+ASr
value and its value is
PbA
. The fan
are at minimum speed (
AMi)
when the
temperature read by fan probe is
SET+ASr
and the fan is at maximum speed (
AMA
) when
the temperature is
SET+ASr+PbA
.
NOTE:
to use properly this function FAP has to be set as the thermostat probe.
