Control Alarms; Eev Motor Alarm - Carel EVD evolution User Manual

ENG
The behaviour of the driver in response to probe alarms can be confi gured,
using the manufacturer parameters. The options are:
•
no action (control continues but the correct measurement of the
variables is not guaranteed);
•
forced closing of the valve (control stopped);
•
valve forced to the initial position (control stopped);
•
use the backup probe (valid only for probe S1 and S2 alarms, control
continues).
Parameter/description
CONFIGURATION
S1 probe alarm manag.:
1=No action
2=Valve forced closed
3=Valve at fi xed position
4=Use backup probe S3
S2 probe alarm manag.:
1=No action
2=Valve forced closed
3=Valve at fi xed position
4=Use backup probe S4
S3 probe alarm manag.:
1=No action
2=Valve forced closed
3=Valve at fi xed position
S4 probe alarm manag.:
1=No action
2=Valve forced closed
3=Valve at fi xed position
CONTROL
Valve opening at start-up (evaporator/valve
capacity ratio)

9.4 Control alarms

These are alarms that are only activated during regulation.
Protector alarms
The alarms corresponding to the LowSH, LOP, MOP and High Tcond
protectors are only activated during control when the corresponding
activation threshold is exceeded, and only when the timeout defi ned by
the corresponding parameter has elapsed. If a protector is not enabled
(integration time= 0 s), no alarm will be signalled. If before the expiry
of the timeout, the protector control variable returns back inside the
corresponding threshold, no alarm will be signalled.
Note: this is a likely event, as during the timeout, the protection
function will have an eff ect.
If the timeout relating to the control alarms is set to 0 s, the alarm is
disabled. The protectors are still active, however. The alarms are reset
automatically.
Low suction temperature alarm
The low suction temperature alarm is not linked to any protection
function. It features a threshold and a timeout, and is useful in the event
of probe or valve malfunctions to protect the compressor using the relay
to control the solenoid valve or to simply signal a possible risk. In fact,
the incorrect measurement of the evaporation pressure or incorrect
confi guration of the type of refrigerant may mean the superheat
calculated is much higher than the actual value, causing an incorrect and
excessive opening of the valve. A low suction temperature measurement
may in this case indicate the probable fl ooding of the compressor, with
corresponding alarm signal. If the alarm timeout is set to 0 s, the alarm is
disabled. The alarm is reset automatically, with a fi xed diff erential of 3°C
above the activation threshold.
"EVD evolution" +0300005EN - rel. 3.1 - 25.07.2011
Relay activation for control alarms
As mentioned in the paragraph on the confi guration of the relay, in the
event of LowSH, MOP, High Tcond and low suction temperature alarms,
the driver relay will open both when confi gured as an alarm relay and
confi gured as a solenoid + alarm relay. In the event of LOP alarms, the
driver relay will only open if confi gured as an alarm relay.
Parameter/description
CONTROL
LowSH protection threshold
Def.
LowSH protection integration time
Valve at fi xed position
LOP protection threshold
LOP protection integration time
MOP protection threshold
Valve at fi xed position
MOP protection integration time
ADVANCED
High Tcond threshold
High Tcond integration time
ALARM CONFIGURATION
No action
Low superheat alarm timeout
(LowSH)
(0= alarm DISABLED)
Low evaporation temperature alarm
No action
timeout (LOP)
(0= alarm DISABLED)
High evaporation temperature alarm
timeout (MOP)
(0= alarm DISABLED)
50
High condensing temperature alarm
timeout (High Tcond)
Tab. 9.d
(0= alarm DISABLED)
Low suction temperature alarm
threshold
Low suction temperature alarm
timeout

9.5 EEV motor alarm

At the end of the commissioning procedure and whenever the driver is
powered up, the valve motor error recognition procedure is activated.
This preceded the forced closing procedure and lasts around 10 s.
The valve is kept stationary to allow any valve motor faults or missing
or incorrect connections to be detected. In any of these cases, the
corresponding alarm is activated, with automatic reset. The driver will go
into wait status, as it can longer control the valve. The procedure can be
avoided by keeping the respective digital input closed for each driver. In
this case, after having powered up the driver, forced closing of the valve
is performed immediately.
it is recommended to switch the driver off and on again to realign the
position of the valve. If this is not possible, the automatic procedure for
synchronising the position may help solve the problem, nonetheless
correct regulation will not be guaranteed until the next synchronisation.
44
Def.
5
15
-50
0
50
20
80
20
300
300
600
600
-50
300
Important: after having resolved the problem with the motor,
Min. Max. UOM
-40 (-72) superheat K (°F)
set point
0 800 s
-60 (-76) MOP thre- °C (°F)
shold
0 800 s
LOP th- 200 (392) °C (°F)
reshold.
0 800 s
-60 (-76) 200 (392) °C (°F)
0 800 s
0 18000 s
0 18000 s
0 18000 s
0 18000 s
-60 (-76) 200 (392) °C (°F)
0 18000 s
Tab. 9.e