54
Capacity
controller RS8ER302 © Danfoss 2016-02
AK-CH
650
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8. Set monitoring of compressor
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9. Set operation time for compres-
sor
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10. Set times for safety cutouts
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11. Set Misc. function
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12. Setting pump functions
Configuration - continued
The settings only apply to the
relay that cuts the compressor
motor in and out.
They do not apply to unloaders.
If the restrictions overlap, the
controller will use the longest
restriction time.
In our example we use:
- Frost protection
- One general safety monitoring
unit for each compressor
(The remaining options could
have been selected if specific
safety controls for each
compressor had been required)
Set min. OFF-time for the com-
pressor relay
Set min. ON-time for the compres-
sor relay
Set how often the compressor is
allowed to start
reduced and the entire condenser capacity will be cutin.
If the limit is exceeded, the entire compressor capacity will
be cutout
Pc Max limit
Maximum value for the condenser pressure in °C
3 K below the limit, the entire condenser capacity will be
cutin and the compressor capacity reduced.
If the limit is exceeded, the entire compressor capacity will
be cutout.
P0 Min limit
Minimum value for the suction pressure in °C
If the limit is reduced, the entire compressor capacity will be
cutout.
P0 min delay at start-up (0-600 sec)
Low pressure cut-out can be delayed for cut-out to be
avoided.
Safety restart time
Common time delay before restarting the compressor.
(Applicable to the functions: "Sd max. limit", Pc max. limit"
and "P0 min. limit).
SH Min alarm
Alarm limit for min. superheat in suction line.
SH Max alarm
Alarm limit for max. superheat in suction line.
SH alarm delay
Time delay before alarm for min./max. superheat in suction
line.
8 - Compressor safety
Frost protection
Choose whether an overall, joint security inlet for all com-
pressors is desired. If the alarm is activated, all compressors
will be disengaged.
Oil pressure etc
Define here whether this type of protection should be con-
nected.
For "General", there is a signal from each compressor.
9 - Minimum operation times
Configure the operation times here so "unnecessary opera-
tion" can be avoided.
Restart time is the time interval between two consecutive
starts.
10 - Safety timer
Cutout delay
The time delay resulting from drop-out of automated safety
measures and until the compressor-error is reported. This
setting is common for all safety inputs for the relevant
compressor.
Restart delay
Minimum time that a compressor should be OK after a safety
cut-out. After this interval it can start again.
11 - Misc. functions
Alarm monitoring S4
Alarm option in the case of too high and too low S4
Different time delays are connected
Liq. inj suction line
Select the function if a liquid injection is required in the
suction line in order to keep the discharge gas temperature
down.
Extra cooling req.
The controller can activate a relay if it cannot keep the tem-
perature down. The function has a temperature setting and
two delay times.
12 - Pumps
No of pumps (0, 1 or 2)
Cold pump control
Pump operation is defined here:
0: No pumps in operation
1: Only pump 1 in operation
2: Only pump 2 in operation
3: Both in operation
4: Operating time equalisation. Start before stop
5: Operating time equalisation. Stop before start
Pump cycle time
Operating time before changeover to the second pump
(1-500h)
Pump switch time
Overlapping time, where both pumps are in operation with
"start before stop" or break time with "stop before start"
(0-600 sec)
Pump safety
Select Common if monitored with flow switch
Select Individual if DI-signals are received from relays
Pump alarm delay
Delay from drop out to alarm.
In our example we do not use
these functions.
