Technical data

Technical Manual Cold Storage Controllers TKP / TKC x130 - x140 Page 13
Cooling
Control circuits
This controller is able to control up to 4 indepen-
dent cooling circuits, each with an own setpoint.
Temperature sensors
Two control sensors can be assigned to each
circuit. If one of them gets warmer than setpoint
plus hysteresis then cooling starts. Cooling doesn’t
stop until both have achieved the setpoint.
Cooling
Cooling is controlled by switching the output relay.
In case of power loss or controller defects the
contacts must switch in a position which is safe for
the application. For this reason we are using the
N/O-contact for refrigeration applications (fail-safe:
open contacts). For freezing applications we use
the N/C-contacts (fail-safe: closed contacts).
This can be set by parameter "cooling mode"
(mode page). The point of cut-off is always the
valid setpoint.
The selection of this parameter also affects to the
switching characteristic of the fan relay.
The refrigeration relay can be disabled via interface
(see chapter "networking via E-Link").
Refrigeration delay after power up
The start of refrigeration after power-up resp.
mains loss can be delayed by parameter
" refrDlyAftMnsOff " (Setpoint Page). In plants with
many cold storages this function prevents that
after power-up all solenoid valves open at the
same time, even though not enough machine
power is present yet.
setpoint
heatin
g
ON
hysteresis
cold
off
hysteresis
refri
g
.ON
warm
coolin
g
= relay ON
setpoint
cold
relay OFF
hysteresis
warm
cold
setpoint
hysteresis
warm
freezin
g
=
relay OFF
relay ON
refrigeration
freezing
refri
g
. relay
coolin
g
mode=
refri
g
-
eration
M
L
fan relay
refri
g
.relay
coolin
g
mode=
freezin
g
M
L
fan relay
Heating function
For one relay it is possible to assign the function of
heating circuit 1.
The setpoint is the cut-off of heating and cooling at
the same time.
The cut-in will be:
• for cooling at setpoint + hysteresis and
• for heating at setpoint - hysteresis.
Second setpoint (night operation)
For each of the 4 circuits a second setpoint is
available ( 2nd setp Ch X ). This can be used for
night operation or other energy savings. The
toggling between these setpoints can be made by
the internal clock or by digital input. The setpoint
which is in use at the moment is marked by two
arrows like: „—> -20,0°C <—“. In the actual values
page you see also if day or night setpoint is in use.
Internal toggling
The parameters „ night setpt ON “ (mode page)
and „ night setpt OFF “ determine the period
when the 2nd setpoint will be active. If the
function 'night settings' is assigned to one of the
digital inputs, it must be connected to mains
phase. If the internal timer is not used, set ' night
setp. ON ' and 'night setp. OFF ' times to „OFF“.
External toggling
If the 'night settings' input is open, the 2nd
setpoint is activated all time and the internal
timer is disabled. With this digital input to mains
phase, the normal (1st) setpoint is activated and
the internal timer is enabled.
Runtime Monitoring
The controller monitors the total running hours per
day of the cooling outputs. This values are displayed
under parameters „ run time refr. x “ for each circuit.
One day counts from the time of the parameter
„ runtime mess at “ (mode page) until the same time
of the next day.
Example:
" runtime mess at " set to 11:00.
Monitoring time range is from 11:00 o'clock day
1up to 10:59 o'clock day 2.
A parameter „ cooling limit “ can be set to a
reasonable value (hours per day) which, when
exceeded on three days in a sequence, will cause
an alarm at the hour programmed by „ runtime
mess at “. Then the alarm relay will be de-activated
and the alarm LED goes on.
This alarm will be cancelled automatically 1
hour later.
30 minutes
emer
g
enc
y
o
p
eration
in %
ON
coolin
g
OFF
coolin
g
ON
OFF
Emergency Operation of temperature
control
If all room sensors of a circuit fail, the controller will
turn to an emergency operation mode for this
circuit. The refrigeration relay switches on in certain
intervals, preset by „ emergency operat “ (mode
page). The total period is 30 minutes. E.g.: selecting
emergency operation to 40% means 12 minutes
on, 18 minutes off. As soon, as the sensor works
correctly, emergency operation is finished and
normal temperature control continues.
Operation with a single compressor
If a single compressor is controlled by a refrigeration
relay, it is suggestive to have an idle time to
prevent the machine from damages caused by
short cycle operation. The compressor can restart
only after the timer " compr. pause " (setpoint page)
is run down. The remaining time up to the
compressors restart can be read at " rem.compr
pause X " (actual page).
Second Set of Setpoints
The controller offers two sets (layers) of setpoints,
where the first layer of setpoint is used during
normal operation and the alternative layer of
setpoints with other temperatures is used e.g. for
other products which will be stored only sometimes.
For each layer there are parameters for the
setpoints, the night setpoints, warning offsets and
low temperature warning. The names of the se-
cond set parameters begin with ' alt ....'.
Toggling between the setpoint layers
1. internal: with parameter „ setpoint layer “
2. external: assign function „setpoint layer“ to
a digital input. If connected to
mains phase, the 2nd layer is in
use.