FISCHER Mess- und Regeltechnik GmbH
Installation | 3
BA_EN_DE45_ATEX_LCD
11/40
If the pressure sensing lines are already pressurised at the time of commission-
ing, zero-point control and adjustment cannot be performed. In such cases, the
device should be only connected to the mains without the pressure sensing
lines.
3.3 Electrical connection
3.3.1 Electrical connections
WARNING
Operation in areas at risk of explosion
If operated in explosive areas, the electrical data of the unit and the valid local
regulations and guidelines for the installation and operation of electrical systems
in explosive areas must be observed. (e.g. DIN EN 60079)
• By authorized and qualified specialized personnel only.
• When connecting the unit, the national and international electro-technical
regulations must be observed.
• Disconnect the system from the mains, before electrically connecting the
device.
• Install the consumer-adapted fuses.
• Do not connect the connector if strained.
If units are used in potentially explosive areas, the personnel must receive addi-
tional training or briefings or have a permit to work ion explosion-protected units
in potentially explosive systems.
3.3.2 3-wire connection
The device is connected as follows in a 3-wire switch:
The connection "Signal ground“ (-Sig) is connected internally to the supply
ground. It only serves as the ground connection for the output signal. This
means that the output signal is free of interference levels on the power supply
lines.
The supply voltage (24 V DC) may not exceed 32 V DC. The supply circuit must
be protected by a slow 200 mA fuse.
Reception
Delivery
AC
DC
Sensor
Signal
+U
b
- U
b
- Sig
+Sig
+U
b
- U
b
p
1
3
2
4
200 mAT
Fig. 4:
3L-switch with internal bridge
