ECKELMANN VS 300 - Low Pressure Monitoring

Function of VS 300
44
Doku-Version 2.05 - Firmware 2.10 - 15. September 2017
4.4.2 Low pressure monitoring
All compressors are unloaded if low pressure drops to a definable limit. When the pressure rises to the level pro
portional to the t
0
setpoint, the compressors are re-loaded progressively as described above. Alarm is generated
after a delay has elapsed. Delay and priority of the alarm are definable. The alarm limit is entered in _C (Param
eter S227 / S267).
ZNR. 51203
64 930 E1
Control algorithm LP monitoring
neutralzone (NZ)
t
Time
0
Suction pressure
t
0 Setpoint
LP-Limit
Compressor shutdown
Alarm is signaled
Compressor load
Alarm delay
4.4.3 Monitoring of the t
c
/t
0
difference
If the high pressure falls to a level below the LP setpoint the installation no longer starts. In order to prevent this
a minimal temperature difference between the t
C
actual value and the t
0
setpoint can be programmed. If the dif
ference falls below the defined limit value, the t
0
setpoint is lowered so that the difference is maintained.
This leads to a compressor start-up which generates an increase in the high pressure. If the temperature differ
ence exceeds the defined setpoint, the t
0
setpoint is raised by 1 Kelvin per minute until the setpoint derived from
the t
0
characteristic curve has been reached again.
The temperature difference can be programmed in the menu 3-4 Monitoring CL1/CL2 via the parameter Min to
diff. If ”---” is entered then the t
0
lowering is deactivated.
t
Time
ZNR. 51203
82 830 E2
c Act.
Min. t - t -Diff.
0
t -Subsidence
t
0 Setp.
C
0
1 K/min
t
c min.
The function can only be activated when CL1 is parameterised as low pressure circuit (NT1 or LT1)
and CL2 as high pressure circuit (HP) (see chapter 5.3.2.4 - Configuring the controller).