Installation __________________________________________________________________________
RF-MCGARDPRO
Hubbell Power Systems, Inc.
–
RFL™
Products
July 1, 2022
©2022 Hubbell Incorporated
3-8
The use of RS-485 provides remote management of Remote Telemetry Units (RTUs) or
Intelligent Electronic Devices (IEDs) such as the HPS/RFL GARD Pro system without requiring
a separate Ethernet connection for each IED.
IED
RFL™ GARD
Pro™ System
RS-485
RS-485
Slaves
RS-485
IED
RTUMaster
TCP/IP
TCP/IP
Master
Master
Network 2
Master
Network 1
Figure 3-4. Network connections
The diagram shows an HPS/RFL GARD Pro system with two masters through the rear Ethernet
port and a third master through the RTU on RS-485. The three masters can be in the same or
different networks.
3.5.4 RS-232 connections (Management port)
This port provides an IRIG-B reference signal from the HPS/RFL GARD Pro system. See section
3.5.5 IRIG-B timing connection
IRIG-B is part of a timing standard that varies primarily by rate. The timing for IRIG-B is a 100
Hz pulse rate which the HPS/RFL GARD Pro system can supplement with an optional GPS
signal.
The timing maintains the system clock, so the time of remote devices accurately reports the
messages sent back to the controller. The standard was established before GPS so industries that
need properly correlated times adopted one of the IRIG timecodes. IRIG-B is common in the
data handling systems, communication systems and telemetry systems such as power industry.
