9
After electrical connection the internal fan turns on
and circulates the enclosure air. This helps assure
even temperature distribution within the enclosure.
The condenser fan and compressor are controlled
by the Comfort controller. The minimum break time
is 3 min. The switching difference is 5 K, but
can be set in the range 2 – 10 K. To avoid short
switching cycles and hence the danger of
inadequate or only partial cooling in some
sections of the enclosure, the switching difference
should be set to be only as low as necessary.
For economic reasons (energy saving), the
nominal value of the internal enclosure
temperature T
i
should also be set to be only
as low as necessary.
6.2.1 Operation of the Comfort controller
(see diagram 13.1 Programming)
The display terminal H1 consists of a 3 position
7-segment display which indicates the enclosure
internal temperature in °C or °F (changeable) as
well as any fault codes. The actual enclosure
internal temperature is constantly displayed on
H1. When a system message is generated, this
alternates in the display with the current internal
enclosure temperature. While programming the
unit, the programming level and prescribed value
are also displayed.
Test mode
By simultaneously holding down keys H2
(
°C key) and H4 (
/set key) for 5 seconds, the
cooling unit will commence cooling operation,
irrespective of the setpoint. The door limit switch
function is disregarded in such cases. After
approximately 5 minutes or upon reaching 15°C,
the device deactivates cooling operation once
again.
6.2.2 Programming
(see 13.1 Comfort controller
programming)
In the EEPROM of the Comfort controller various
parameters are stored which can be changed by
using the buttons H2, H3 and H4. 24 changeable
parameters can be set via 24 programme levels in
the stated ranges (max. and min. values).
To this end, input code “22” is required
(see diagram 13.1).
The H2, H3 and H4 keys are multiple occupancy.
To access programming mode, set 5 sec is to be
pressed and held down.
Primary occupancy (only diode displays):
H2: °C, H3: °F, H4: Alarm
Secondary occupancy (for programming):
H2: Arrow upwards, H3: Arrow downwards,
H4: set
Programming via diagnostic software (order no.
SK 3159.100) is also an option. The programming
cable interface is the connecting cable plug,
located on the rear of the Comfort controller. To do
this, the louvred grille also is to be removed if
necessary.
6.2.3 System messaging equipment
All system messages at the cooling unit are
recorded and displayed as an error number
by H1. System messages alternate in the display
with the current internal enclosure temperature.
(see 12. Comfort control fault display and error
analysis).
6.2.3.1 System message contacts
(K1 and K2; potential free)
Both relays are normally closed.
All system messages assigned to an individual
relay result in it opening. If the control voltage
fails, this also results in the relay opening and can
hence be captured and documented in the log
file. According to individual weighting, all system
messages can be assigned to both relays or
suppressed. Terminal strip X3 provides the
connection. See the wiring diagram for contact
data and occupancy.
K1/K2 fault signal relay (normally open contact):
Terminal 3: Fault signal relay 1
Terminal 4: Voltage supply connection for both
fault signal relays
Terminal 5: Fault signal relay 2
(see the circuit diagrams on page 37).
7. Supplementary functions
7.1 Filter mat use and changing
The PU foam filter mat available as an accessory
is coarse and filters large dust particles or fluff
from the air. Metallic filter mats are used to trap
oil condensate. These are also available as an
accessory. Subject to the suction of the blower
being high enough, fine dust is blown through
the filter mat and the external circuit of the unit.
This does not affect the unit's operation.
Fig.7.1
Filter mat replacement
7.2 Filter mat monitoring
Function of the filter mat monitor:
The filter mat is monitored for soiling by measur-
ing the temperature difference in the external cir-
culation of the cooling unit (see diagram 13.1:
Programming on page 45). In the event of any
filter mat soiling, the temperature difference will
increase. The nominal value of the temperature
difference in the external circuit is matched to the
relevant operating points in the characteristic
fields. Hence there is no requirement to adjust the
nominal value for different unit operating points.
7.3 Door limit switch S1
(supplied by customer)
Where a door limit switch is used and the enclo-
sure door is open (contact is closed when door is
open), the cooling unit (fans and condenser) will
switch off after approx. 15 s. This only applies to
devices with a Comfort controller and devices
with a three-phase connection to the basic con-
troller. For devices with a basic controller (115 V,
230 V and 400 V, 2~), the internal fan is not
switched off when using a door limit switch.
Thereby avoiding an increase in condensation
while the door is open. To avoid cyclic operation,
switch-on of condenser and external fan is
delayed by about 3 minutes after the cooling unit
has been switched off.
The internal fan will start up after about 15 s on
closure of the door. Connection is made at the
terminals 1 and 2. The extra low voltage is
supplied by the internal power pack, current is
approx. 30 mA DC. Each door limit switch must
only be assigned to one cooling unit. Several door
limit switches may be operated on one cooling
unit (parallel connection). The minimum cross-
section of the connection cable is 0.3 mm
2
for a
cable length of 2 m. The resistance of the door
limit switch contact must not exceed a maximum
of 50
Ω
.
Only connect the door limit switch to the
cooling unit’s own DC supply!
7.4 Interface X3 (option)
(Connector X3)
Note!
The electrical signals at the interface are of an
extra-low voltage (not extra-low safety voltages
to EN 60 335).
The 9-pin SUB-D socket X3 can be used to
connect additional interface cards for integrating
cooling units with higher level monitoring systems.
These cards are also available as an accessory.
(Interface card: Model No. SK 3124.200).
1.
2.
8. BUS system
(Model No.: Master-slave cable SK 3124.100)
8.1 General
The BUS system allows a maximum of 10 cool-
ing units to be interconnected.
As a result, the following functions are available
to the operator:
Parallel unit control (the cooling units in the
network can be simultaneously switched
on and off)
Parallel door status messages (“door open”)
Parallel collective fault message
The data exchange is carried out using master-
slave cables (shielded, two-wire leads). All units
are assigned an address. This address also
includes the ID for “master” or “slave”.
8.2 Installation notices for the X2 interface
(Jack X2)
Note!
The electrical signals at the interface are of an
extra-low voltage (not extra-low safety voltages
to EN 60 335). Always heed the following notes!
De-energise the cooling units to be
connected.
Ensure proper electrical insulation.
Make sure the cables are not laid in parallel
to power lines.
Make sure that the lines are short.
8.3 Programming the cooling unit
See diagram 13.1 for details on programming.
ID’s:
Note
Only one unit may be configured as master; the
address ID must match the number of slave
units.
The individual slave units must have different
addresses; the addresses must be in ascending
order (without gaps in between).
Example:
1 master cooling unit with 2 slave cooling units
(see wiring example of master/slave and door
limit function, page 42/43).
Master cooling unit
Slave cooling unit
00
Basic state
00
Basic state
01
Master
with 1 slave
11
Slave
with address 1
02
Master
with 2 slaves
12
Slave
with address 2
03
Master
with 3 slaves
13
Slave
with address 3
04
Master
with 4 slaves
14
Slave
with address 4
05
Master
with 5 slaves
15
Slave
with address 5
06
Master
with 6 slaves
16
Slave
with address 6
07
Master
with 7 slaves
17
Slave
with address 7
08
Master
with 8 slaves
18
Slave
with address 8
09
Master
with 9 slaves
19
Slave
with address 9
Master
02
Slave
11
Slave
12
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