Connection For Ma Loop Configuration As Isolated Output; Cabling Recommendations; Earthing Recommendations; Modbus - Honeywell SEARCHLINE EXCEL PLUS Technical Manual

36 Chapter 6 Electrical Installation
6.2.5 Connection for mA Loop Configuration as Isolated Output
6.2.6 Cabling Recommendations
The cable used must be appropriate for the hazardous area classification and must meet local, national and company
regulations. The use of industrial grade, screened field cable is recommended.
An example may be a 3–core copper cable with screen (minimum 90% coverage) and suitable mechanical protection
(e.g. steel wire armour) to suit an M25 or 3/4" NPT gland entry or conduit, suitable when mA loop and Modbus are used while
relay outputs are not utilized.
The allowable conductor size for the terminals is 0.25–2.5 mm² (24–12 AWG). The terminals will accept only wire sizes
(solid-core or stranded) in this range. The temperature rating of the conductors and cable glands should be greater than
80 °C (176 °F). The terminals should be torqued between 0.5 Nm to 0.6 Nm (0.368-0.442 lb.ft).
Ensure that the cable gland is installed correctly and fully tightened. All unused cable/conduit entries must be sealed with
a suitable certified blanking plug. Use appropriate and certified cable glands, adapters and/or cable fittings to meet local
standards.
6.2.7 Earthing Recommendations
CAUTION
!
Any earthing regime employed must avoid earth loops.
The following information is provided to assist with proper earthing of the transmitter and receiver:
• The transmitter and receiver have both INTERNAL and EXTERNAL earth points provided (see Electrical Connections).
This is to facilitate connection of the instrument to protective earth.
The INTERNAL earth point is marked with ground symbol in circle
connection. Internal earth must be at least equal in mm
The EXTERNAL earth point is marked with ground symbol without circle
connection, which provides facility for connection of field wiring conductors of at least 4mm
• Field cable screens should be connected to instrument earth at the control room. The other end of the field cable
screen should be suitably terminated or isolated. It should not be connected to internal earth point.
6.2.8 Modbus
Refer to Chapter 10 Communications of this manual for more information on Modbus.
Figure 24. mA loop configuration as isolated output
Searchline Excel™ Plus / Searchline Excel™ Edge – Technical Manual
It shall be used for the equipment grounding
to the incoming power conductors.
2
It provides a supplementary bonding
.
2