Yokogawa DO202 2-Wire Dissolved Oxygen Analyzer - Manual (Page 8)

IM 12A00A01-61E
Foundation Fieldbus 3-3
3-2-1-2. Cables, terminals and glands
The EXA202 is equipped with terminals suitable for the connection of finished cables in the size range:
0.13 to 2.5 mm (26 to 14 AWG). The glands will form a tight seal on cables with an outside diameter in the
range of 6 to 12 mm (0.24 to 0.47 inches).
The following instruments are required for use with Fieldbus devices:
• 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 EXA Fieldbus communication type.
Two or more EXA devices or other devices can be connected.
• Host
Used for accessing field devices. A dedicated host (such as DCS) is used for an instrumentation line
while dedicated communication tools are used for experimental purposes. For operation of the host, refer
to the instruction manual for each host. No details of the host are explained in the rest of this material.
• Cable
Used for connecting devices. Refer to “Fieldbus Technical Information” (TI 38K03A01-01E) for details of
instrumentation cabling.
Fieldbus uses twisted pair wires. To meet the Electro Magnetic Interference standards a shielded twisted
pair is obligated.
Refer to Yokogawa when making arrangements to purchase the recommended equipment.
Connect the devices as shown in Figure 3.4. Connect the terminators at both ends of the trunk, with a mini-
mum length of the spur laid for connection.
The polarity of signal and power must be maintained.
EXA
Power
supply
Terminator HOST Coupler/terminator
Figure 3.4 Cabling
NOTE
Before using a Fieldbus configuration tool other than the existing host, confirm it does not affect
the loop functionality in which all devices are already installed in operation. Disconnect the relevant
control loop from the bus if necessary.
IMPORTANT
Connecting a Fieldbus configuration tool to a loop with its existing host may cause communication data scrambles
resulting in a functional disorder or a system failure.