Installation, Operation and Maintenance Manual
VCIOM-15345-EN Rev. 1
February 2022
33
Communication Protocols
Section 5: Communication Protocols
Section 5: Communication Protocols
Digital control networks can interface with several different network protocols through the
use of a Communication Adaptor Module (CAM), and currently, Modbus, FOUNDATION™
Fieldbus, and HART protocols are supported. All networks offer real-time data acquisition,
diagnostics and alarms.
5.1
Modbus RTU
All standard Modbus function codes are supported. Up to 254 actuators can be installed
in a single network, and the overall length of network cabling can be extremely long
without degrading network performance or response time. Length of cable between
each actuator, or between controller and first actuator in network, can be up to 1500 m
(5000 ft) and there is no need to use separate repeaters. Total network distance can be up
to 320 km (200 miles).
Fully redundant networks comprising a serial loop topology are a standard feature, and
no single cable fault, open-circuit, short-circuit, or ground fault will cause a loss of
communication to any actuator. Hot-standby, redundant network masters are a
standard option.
5.1.1
Serial E>Net Redundant Loop Topology
—
Two data paths to each device from network master
—
Open-circuit and short-circuit protected
—
Redundant cabling included
—
Long cable distances can be installed
—
Maximum distance between valves can be up to 1500 m (5000 ft)
—
Total network distance can be up to 320 km (200 miles)
—
Maximum number of valves in network can be 254
—
Redundant “hot-standby” network master option available
Figure 13
Modbus/Serial E>Net Redundant Loop Topology
Primary Network
Master
RS-232, RS-485, or RS-422 Modbus
RS-485, Modbus, Twisted Shielded-Pair Cable, 9600 Baud
