Carel Heos, User Manual

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32
ENG
Heos +0300078EN - rel. 1.6 - 23.11.2017
PM2 represents the integration time for the maximum evaporation
pressure protection function. This replaces normal PID control during
MOP status.
•
PM2 = 0 ==> MOP protection and alarm disabled
PM3 represents the alarm activation delay after exceeding the MOP
threshold. When the alarm is activated, the following occur:
Message ‘MOP’ shown on the display
The buzzer is activated
The alarm features automatic reset when the evaporation pressure falls
below the threshold PM1.
LSA - Low suction temperature
When the suction temperature falls below the threshold, the alarm is
activated after the set delay, closing the electronic valve. The alarm is
reset when the suction temperature exceeds the set threshold plus the
hysteresis. Reset is automatic for a maximum of four times in a two hour
period. Upon the fi fth activation in such period, the alarm is saved and
requires manual reset from the user terminal or supervisor.
Par. Description Def U.M. Min Max
P11 LSA: low suction temperature threshold -40.0
(-40.0) °C
(°F) -50.0
(-58.0) 30.0
(86.0)
P12 Low suction temperature alarm delay
0: alarm disabled (NO);
120 s 0 300
P11 represents the suction temperature below which the alarm is
activated, after the corresponding delay. The threshold for resetting the
alarm is represented by this threshold plus a 3°C hysteresis.
P12 represents the alarm activation delay after exceeding the threshold
P11. When the alarm is activated, the following occur:
•
message ‘LSA’ shown on the display;
•
the buzzer is activated
The alarm features automatic reset for the fi rst four activations over a two
hour period, then becomes manual reset.
•
P12 = 0 ==> LSA alarm disabled
time
T
suct
P12
ON
OFF
ALARM
ON
P11
OFF
LSA
3°C
Fig. 6.ab
Key
T_SUCT Suction temperature LSA LSA protection
P11 LSA: low suction temperature threshold ALARM Alarm
P12 LSA: LSA alarm delay
LOP Minimum evaporation pressure
This function is used to prevent the evaporation pressure from remaining
excessively low for too long. When the evaporation pressure, expressed
in degrees (saturated), falls below the threshold, the LOP protection
is activated, which adds an integration action to normal PID control,
specifi cally devised to be more reactive as regards the opening of the
valve. PID control remains active, as the superheat must continue to
be monitored as to avoid fl ooding the compressor. The LOP alarm is
delayed from the activation of the protection function, both are reset
automatically when the pressure value, in degrees (saturated), exceeds
the threshold.
Par. Description Def U.M. Min Max
PL1 LOP -40.0
(-40.0)
°C
(°F) -50.0
(-58.0) MOP
PL2 LOP: Low evaporation temperature integral time 10 s 0.0 999
PL3 LOP: Low evaporation temperature alarm delay 120 s 0 300.0
PL1 represents the evaporation pressure, expressed in degrees
(saturated), below which the LOP protection is activated. The protection
is deactivated immediately when the pressure exceeds this threshold.
PL2 represents the integral constant used during the activation of the
LOP protection. This integral time is summed to normal PID control.
•
PL2 = 0 ==> LOP protection and alarm disabled
PL3 represents the alarm activation delay after exceeding the LOP
threshold. When the alarm is activated, the following occur:
message ‘LOP’ shown on the display;
the buzzer is activated.
The alarm features automatic reset when the evaporation pressure rises
above the threshold PL1.
PL3 = 0 ==> LOP alarm disabled
High superheat
To avoid excessively high superheat values, an alarm threshold and
activation delay can be set.
When superheat exceeds the threshold, the system immediately enters
high superheat status and activates a function that closes the electronic
valve more quickly. If the device remains in high superheat status for a
certain period, an alarm is activated, with the display showing the message
‘HSh’. The high superheat signal features automatic reset, when the
condition is no longer present or the controller is switched off (standby).
Par. Description Def U.M. Min Max
Pa High superheat threshold 35.0
(95.0) °C
(°F) 0.0
(32.0) 50.0
(122.0)
Pb High superheat alarm delay 600 s 0 999
Manual valve positioning (screen Bb05)
PMP is used to enable/disable manual valve positioning.
PMP = 0: manual positioning disabled;
PMP = 1: manual positioning enabled.
If manual positioning is enabled, PMu is used to set the manual opening
of the electronic valve. The value is expressed in steps.
Par. Description Def U.M. Min Max
PMP Enable manual expansion valve positioning
0 = disabled (NO); 1 = enabled (YES)
0 -- 0 1
PMu Manual expansion valve position 0 steps 0 480
6.11 Anti-sweat heater or fan modulation
IAnti-sweat heaters are controlled by comparing dew point calculated
based on the room temperature and humidity, and the temperature
of the showcase glass, measured by a probe or estimated using the
showcase outlet, intake and room temperature. Two types of anti-sweat
heater control are available:
•
PI (proportional, integral);
•
fi xed activation (manual control).
The conditions for activation of the algorithms are as follows:
Algorithm Activation condition
PI rHd > 0
fi xed activation (manual control) rHd = 0; rHt >0
If the glass probe temperature is estimated (not read), PI control becomes
proportional only. Based on a series of conditions, the PI algorithm ceases
and, if activated, control with fi xed activation commences. In this case,
alarm ACE is signalled on the display.
Condition Cause
Glass temperature
probe not valid physical probe not confi gured or error;
the estimate of the glass temperature probe cannot be used
because the outlet probe or intake probe is not confi gured or
has an error or the room probe is broken or missing
Dew point not valid room humidity and/or temperature probe are not confi gu-
red and operating;
the serial dew point value is not available .