D
escription of each parameter
Setpoint :
is defined as the relay cut OFF.
Hy Hysteresis
This is the difference between the temperature
at which the compressor output is switched OFF
and the temperature at which the output is
switched ON. This is an absolute value, related
to the setpoint.
Example:
Cooling Setpoint = 4 ºC
Differential = 2 K.
The compressor is switched
ON when the temperature
goes over 6 ºC, and is turned
OFF when the temperature
decreases to 4 ºC.
LL/HL Lower & Higher setpoint limit
The setpoint value cannot be adjusted outside
the limits defined by these parameters, to avoid
improper setpoint setting by the user.
CC
Anti short cycle protection
This parameter prevents the compressor from
being turned ON / OFF too often. The value that
you set is the minimum time between two
subsequent switches ON of the output.
Cooling demand
Comp. output
Anti cycle timer
Co
Deep freezing time
This is the time for which the compressor is
forced ON when pressing the deep freezing
cycle key from the faceplate.
AH
High temperature alarm:
High temperature alarm value relative to
setpoint. If your set point is at 4ºC and you want
an alarm 5 K above setpoint, it will be triggered
at 9ºC.
AL
Low temperature alarm:
Low temperature alarm value relative to setpoint.
If your set point is at 4ºC and you want an alarm
3 K below setpoint, it will be triggered at 1ºC.
Ad Alarm
differential:
Useful to avoid alarm oscillations.
For example:
Setpoint = 4ºC,
Max. Temperature alarm = 6 K,
Alarm differential = 2 K.
In this case, when the cold room temperature
exceeds 4+6 = 10ºC for a time greater than
parameter At the alarm is activated; when
temperature drops below 4+6-2 = 8ºC the alarm
is reset
At
Alarm time delay:
Delay between the detection of the temperature
alarm and the activation of the alarm sequences.
This is useful to prevent temporary conditions
from causing an alarm. Furthermore, the
controller automatically ignores the temperature
alarm condition in the following cases:
-
for 20 minutes after the power-ON
-
during defrost and for 20 minutes after the
defrost-end.
dF Defrost
function:
Select the type of your installation and the way
defrost is performed
0 = Electrical defrost (Compressor OFF)
1 = Hot gas defrost (Compressor ON)
dE
Defrost end function:
Select the defrost termination type:
0 = timer based, set with parameter dd
In this case the evaporator sensor is not
required and the fan will restart base on time.
1 = temperature based, set with parameter dt
Note: in any case defrost ends after the time set
on parameter dd.
dt
Defrost termination temperature:
Used only when parameter dE =1. When the
evaporator temperature reaches this value,
defrost automatically ends.
di
Defrost interval time:
This is the time between two subsequent defrost
cycles. This timer will initiate every defrost cycle.
dd
Maximum defrost duration:
If defrost end by time has been selected
(parameter dE=1) defrost cycle will stop after this
time, even if the end temperature has not
reached parameter dt.
When defrost interval time is 1 hour, the
maximum duration is limited to 40 min.
dC
Dripping time:
After defrost is terminated, the compressor is
stopped to allow the evaporator to drip.
Hysteresis
Cooling Setpoint
T ° C
10
CR1
Catalogue Section 9
© 2000 Johnson Controls, Inc.