Bosch Appliances LBC 325X installation manual Reference part list, Grounding strategy

Intellivox DDC Installation Manual Appendix EN 13

3.Appendix.

3.1 Reference part list.

Connectors for external wiring.

Terminal	Description	Manufacturer		Manufacturer code
RS-485	Wago cage clamp connector 5 pin	WAGO	231-105/026-000
	female 5 mm pitch
Audio input	Wago cage clamp connector 6 pin	WAGO		231-106/026-000
	female 5 mm pitch
Failure, Fan, Ambient	Wago cage clamp connector 5 pin	WAGO	231-605
SPL and Temperature	male 5 mm pitch

Table 3 Intellivox external connectors details.

Other installation related accessories.

Description	Type Number
Intellivox swivel bracket 90°	LBC 3270/00
Intellivox swivel bracket 45°	LBC 3271/00
Ambient mic. and temperature sensor	LBC 3262/00

Table 4 Specific installation related accessories.

2.Reduction of RF emission. Although the Intellivox electronics module is well shielded and external connections are de-coupled to prevent RF emission from the internal high speed digital circuits, this protection will not work properly when the chassis has no solid ground reference.

3.Immunity. The GND terminal shorts currents which are induced by (RF) fields in the signal cables effectively to chassis-ground, provided that the cable shield is of sufficiently low impedance.

Other network related accessories.

Description	Type Number
Program set	LBC 3260/00
(Adapter cable+RS-232 to RS-485
adapter+ WinControl CD-Rom)

Table 5 Specific network related accessories

3.2 Grounding strategy.

The ground (GND) terminals on the electronics module serve different purposes.

1.Safety. The GND terminal located at the mains IEC connector provides a direct low impedance path from the metal parts of the chassis to ground. In conjunction with a proper designed mains distribution network, this offers extra safety in situations where the standard class 2 insulation is not sufficient (fire, moisture etc.). Always connect the IEC ground terminal.

To make things even more complex, the RS-485 terminal of the chassis also has a DGND pin, while the ambient SPL/temperature terminal has both GND and AGND pins.

The pins labeled GND are connected directly to the chassis.

The RS-485 DGND pin is not a ground pin, but serves as a reference for the RS-485 AB and YZ wires. Although the DGND pin should be connected to the shielding of the RS-485 cable (when in use), DGND (and ABYZ) has no relation to GND except for the fact that the voltage between DGND and GND is clamped to a maximum voltage of 50 V for reasons of safety and immunity. In an installation with a connected network, the RS-485 cable shield must be grounded at some central position.

•DGND should not be connected to any other ground pin (GND or AGND) on the chassis.

Bosch Security Systems July 2003