Emerson 475, User Manual

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Fieldbus Functionality
4-4
WORKING ONLINE WITH
FIELDBUS DEVICES
The online menus display data for the device to which you are connected, and they
display critical, up-to-date process information, including the segment Live Device List,
Block Lists, device menus, and parameter information.
NOTE
It is normal for processes to take longer the greater the amount of scheduled
communication. This is influenced by the number of devices and the control methods
in place.
Connecting to a Fieldbus
Device
Connect the 475 Field Communicator by using the lead set with the appropriate
connectors in parallel with the device. Due to measurement circuitry, the 475 Field
Communicator fieldbus connectors on the communication terminals are polarity
sensitive. An error message appears if the lead set is connected incorrectly.
For information about Intrinsically Safe connections, see Appendix B.
NOTE
Dynamic variables shown while online represent the digital data being sent from the
device.
Digital communication is susceptible to electrical noise; follow proper wiring
instructions.
Fieldbus Communication Terminals
Three terminals for the lead set are on the top of the 475 Field Communicator. Each
red terminal is a positive connection for its protocol. The black terminal is a common
terminal shared by both protocols. An access door ensures only one pair of terminals
is exposed at any one time; see Figure 4-2. Several markings indicate which pair of
terminals is for which protocol.
Figure 4-2. Fieldbus Communication Terminals and Access Door
Fieldbus Communication Terminal Markings
Access Door
Communication Terminals