GE FVP110, Руководство по обслуживанию, Страница: 106 / 292

FVP 110 Fieldbus Valve Positioner Manual
90
GE Energy
Network Design
1. Select the devices to be connected to the Fieldbus network. Refer to “System
Configuration” on page 87 for selection of the devices.
2. 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
FVP110 is 17 mA.
3. Ensure the cable has a spur in a minimum length with terminators installed at both
ends of the trunk.
Network Definition
Define the Fieldbus network before connection of devices with Fieldbus. To do this:
1. 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). Use a hyphen as a delimiter, as required.
2. Define the node address for devices. This 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 0x14 to 0xF7) can be set. Generally, 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, is allocated from a larger address number (247) side, respectively
(Table 12).
Table 12 Parameters for Setting Address Range
Symbol Parameters Description
V (FUN) First-Unpolled-Node Indicates the address next to the address
range used for the host or other LM device.
V (NUN) Number-of consecutive-
Unpolled-Node Unused address range