Yokogawa EJX930A - Manual (Page 28)

<5. Configuration>
5-1
IM 01C25R03-01E
5. Configuration
This chapter describes how to adapt the function
and performance of the EJX multivariable
transmitter to suit specific applications. Because
multiple devices are connected to Fieldbus,
it is important to carefully consider the device
requirements and settings when configuring the
system. The following steps must be taken.
(1) Network design
Determines the devices to be connected to
Fieldbus and checks the capacity of the power
supply.
(2) Network definition
Determines the tag and node addresses for all
devices.
(3) Definition of combining function blocks
Determines how function blocks are combined.
(4) Setting tags and addresses
Sets the PD Tag and node addresses for each
device.
(5) Communication setting
Sets the link between communication
parameters and function blocks.
(6) Block setting
Sets the parameters for function blocks.
The following section describes in sequence each
step of this procedure. The use of a dedicated
configuration tool significantly simplifies this
procedure. Refer to Appendix 6 when the EJX
multivariable transmitter is used as Link Master.
5.1 Network Design
Select the devices to be connected to the Fieldbus
network. The following are essential for the
operation of Fieldbus.
• Power supply
Fieldbus requires a dedicated power supply. It
is recommended that current capacity be well
over the total value of the maximum current
consumed by all devices (including the host).
Conventional DC current cannot be used as is.
• Terminator
Fieldbus requires two terminators. Refer to
the supplier for details of terminators that are
attached to the host.
• Field devices
Connect the field devices necessary for
instrumentation. The EJX multivariable
transmitter has passed the interoperability
test conducted by The Fieldbus Foundation.
In order to properly start Fieldbus, it is
recommended that the devices used satisfy the
requirements of the above test.
• Host
Used for accessing field devices. A minimum
of one device with the bus control function is
needed.
• Cable
Used for connecting devices. Refer to
“Fieldbus Technical Information” for details
of instrumentation cabling. Provide a cable
sufficiently long to connect all devices. For
field branch cabling, use terminal boards or a
connection box as required.
First, check the capacity of the power supply. The
power supply capacity must be greater than the
sum of the maximum current consumed by all
devices to be connected to Fieldbus. The maximum
current consumed (power supply voltage 9 V to 32
V) for the EJX multivariable transmitter is 15 mA
(24 mA in Software download operation). The cable
used for the spur must be of the minimum possible
length.
5.2 Network Definition
Before connection of devices with Fieldbus, define
the Fieldbus network. Allocate PD Tag and node
addresses to all devices (excluding such passive
devices as terminators).
The PD Tag is the same as the conventional
one used for the device. Up to 32 alphanumeric
characters may be used for definition. Use a
hyphen as a delimiter as required.