78285000_AB 3-1
3
Electrical Installation
3.1 INTRODUCTION
The 7828 density transmitter has two outputs:
•= A direct 4-20mA output, configurable to give an output proportional to a user-specified
range of either
- density
- base or referred density
- temperature
- a selected special function parameter;
•= A Modbus (RS485) interface, giving access to other measurement results, system
information and configuration parameters. The Modbus interface is also used to
configure the 7828, using a PC running ADView software (see Section 4).
It is recommended that both outputs are installed, requiring a total of six wires (two for
each output, and two for power). Although you may not immediately require the Modbus
connection, it may be required for in-situ calibration adjustment and future system
enhancements, and the cost of the additional wires is trivial compared to the expense of
installing them retrospectively.
A number of factors must be taken into account when planning the electrical installation.
These include:
•
••
•=
==
= Power supply (Section 3.2.1)
•
••
•=
==
= EMC (Section 3.2.2)
•
••
•=
==
= Ground connections (Section 3.2.3)
•
••
•=
==
= Cables (Section 3.2.4)
•
••
•=
==
= Surge protection (Section 3.2.5)
•
••
•=
==
= Use in hazardous areas (Section 3.5)
•= Modbus connections (Section 3.4.2)
•
••
•=
==
= Analog connections (Section 3.4.5)
Note: If 7828 is to be used in hazardous areas, the electrical installation must strictly
adhere to the relevant safety drawings, given in Appendix C of the paper manual.
Additional information relevant to hazardous area installation is given in section 3.5.
To Next Page
Loading...