Grounding; Cable Selection; Hazardous Areas - Emerson Rosemount 5708 Reference Manual

Reference Manual
00809-0100-4570, Rev DA
Section 4
Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 23
Cable selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 23
Hazardous areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 23
Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 24
Different connection methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 29
4.1

Grounding

The Rosemount
For internal grounding, use the power cable ground.

For external grounding, use the earth potential equalization of the plant.

4.2

Cable selection

Make sure to select the proper cable for each application.
For RS-485 communication, use shielded, twisted-pair cables with 120Ω impedance. Make sure the

cables are approved for RS-485 communications.
For 4-20 mA communication, use a low resistance cable and make sure the cables are rated for analog

signals.
For daisy chaining, a single 4-wire cable can be used, both for RS-485 and the

24 Vdc power supply. Make sure only to use a proper cable gaging (AWG).
Use 8-13 mm (20-24 AWG) diameter cables to ensure proper and effective sealing of the cable gland

entry opening.
Select a cable suitable for application (indoor or outdoor) and safety certified according to national

regulations.
4.3

Hazardous areas

and power supply units, see
Electrical Installation
Electrical Installation
™
5708 must be grounded electrostatically:
In hazardous areas you should take note of the appropriate regulations, conformity and type of
approval certificates of the sensors and power supply units. For further information on
regulations, see Appendix A: Specifications and Reference
"Wiring" on page
Data. For more information on sensors
24.
Electrical Installation
November 2017
23