Yokogawa Multi Channel Oxygen Analyzer System ZR22/AV550G - Manual (Page 21)

<5. CONFIGURATION>
5-2
IM 11M12D01-61E
• Fieldbus Cable:
Cable is used for interconnecting Fieldbus devices. Refer to Fieldbus Technical Information TI
38K3A01-01E for details. You need enough cable to interconnect all Fieldbus devices. You can
use terminal boards or terminal boxes for running side “spurs” off the “main trunk”, however you
should ensure that the length of such “spur” runs is as short as possible.
Be sure to check that the capacity of the power supply is more than sufficient to supply the sum of the
maximum currents drawn by individual devices, including hosts. The AV550G draws a maximum rated
current of 15 mA over the power supply voltage range 9 to 32 V DC..
5.2 Define network constants
Before connecting devices to (an existing) Fieldbus, determine unique PD tag and node addresses for
all devices (except for passive devices like terminators).
PD tags are like the instrument tag numbers used in measurement and control systems. You can
use up to 32 alphanumeric characters to define the PD tag of each device. You can also use hyphen
delimiters in PD tag names.
Node addresses are used for Fieldbus communications between devices, but PD tag names may
be used as mnemonic aliases for node addresses. You can assign node addresses in the range
(hexadecimal) 10 to F7, which is (decimal) 20 to 247.
Link Master (LM) device addresses should be assigned in sequence starting from the smallest
address (0x14), and basic device addresses should be assigned in sequence starting from the largest
(0xF7). You must set the address range in the Link Master device, using the following parameters:
Table 5.1 Parameters for setting address range
Any devices that are assigned addresses within the “Unused” address range in Figure 5.1 cannot
participate in the Fieldbus. The “basic device” address range is periodically scanned to find any
devices that have newly joined the Fieldbus.
If there are many unused addresses in this range then Fieldbus performance may be severely
degraded (LM devices waiting for nonexistent devices to respond).
T0501.ai
V (FUN) First-Unpolled-Node First unused address
outside the range of LM
(host) addresses.
V (NUN) Number-of-
consecutive-
Unpolled-Nodes
Symbol Parameters Description
Range of unused
addresses.