■ Pressure relief valve:
The pressure relief valve protects the system against excessive pressure. It is factory set.
■ Resistance thermometer:
Monitoring the airend discharge temperature protects the compressed air system from imper‐
missible temperature rises.
■ Door interlock switch:
The machine will stop automatically if a safety interlocked door or panel is opened or removed.
■ Housings and covers for moving parts and electrical connections.
Protect against accidental contact.
4.2.2 Floating relay contacts
Floating relay contacts are provided for the transfer of signals, messages.
Information on location, loading capacity and type of message or signal is found in the electrical
diagram.
If the floating relay contacts are connected to an external voltage source, voltage may be
present even when the machine is isolated from the power supply.
4.3 Operating panel SIGMA CONTROL 2
Keys
Fig. 5 Keys – overview
Position Name Function
1 «OFF» Switches the machine off.
2 «ON» Switch on the machine.
3 «Cancel» Returns to the next higher menu option level.
Exits the edit mode without saving.
4 Design and Function
4.3 Operating panel SIGMA CONTROL 2
28
Operating Manual Rotary screw compressor
SK 901848 21 E