5.8 Operating points and control modes
5.8.1 Machine operating points
STOP
The machine is connected to the power supply.
The
Voltage applied to controller LED is illuminated in green.
The machine is switched off. The
ON LED is out.
READY
The machine has been activated via the «ON» key:
■ The
ON LED is illuminated in green
■ The compressor drive motor has stopped
■ The inlet valve is closed.
■ The minimum pressure/check valve isolates the oil separator tank from the air system
■ The venting valve is open
The compressor motor starts as soon as network pressure drops below the specified network pres‐
sure setpoint (cut-out pressure).
Timing and/or remote control can also influence when the compressor motor starts.
LOAD
The compressor motor runs under load:
■ The inlet valve is open
■ The airend delivers compressed air to the air network.
IDLE
The compressor motor runs unloaded (not for SXC) and consumes less power:
■ The inlet valve is closed.
■ The minimum pressure/check valve isolates the oil separator tank from the air system
■ The venting valve is open
A small volume of air circulates through the bypass bore in the inlet valve, through the airend and
back to the inlet valve via the venting line.
5.8.2 Control modes
In type SXC compressors it is not possible to set the control modes since there is no IDLE
operating point. All menus connected to it are then not available.
In order to ensure that gauge working pressure remains between the specified cut-in and cut-out
pressures irrespective of the consumers’ air demand, the controller switches the machine back and
forth between various operating points, depending on the control mode selected. The control mode
also controls the degree of energy efficiency of the machine.
The machine-dependant venting phase between the LOAD and READY operating points ensures
load changes at minimum material stresses.
5
Design and Function
5.8
Operating points and control modes
50
User Manual Controller
SIGMA CONTROL 2 SCREW FLUID ≥5.0.X
No.: 9_9450 12 E
