Yokogawa EJA115 - Manual (Page 23)

IM 01C22T02-01E 5-1
5. CONFIGURATION
5. CONFIGURATION
This chapter describes how to adapt the function and
performance of the EJA to suit specific applications.
Because multiple devices are connected to Fieldbus, it
is important to carefully consider the device require-
ments 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 sequece each step of
this procedure. The use of a dedicated configuration
tool significantly simplifies this procedure. Refer to
Appendix 5 when the EJA 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 instrumenta-
tion. EJA 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 bus control function is needed.
• Cable
Used for connecting devices. Refer to “Fieldbus
Technical Information” for details of instrumenta-
tion 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 con-
sumed (power supply voltage 9 V to 32 V) for EJA is
16.5 mA. 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.
The node address is used to specify devices for
communication purposes. Because data is too long for
a PD Tag, the host uses the node address in place of
the PD Tag for communication. A range of 20 to 247
(or hexadecimal 14 to F7) can be set. The device (LM
device) with bus control function (Link Master
function) is allocated from a smaller address number
(20) side, and other devices (BASIC device) without
bus control function allocated from a larger address
number (247) side respectively. Place the EJA in the