Chapter 4: System Operation; System Overview; Communications - Emerson PACSystems RX3i User Manual

User manual
GFK-2892G
Chapter 4:
This chapter provides a System Overview and describes:
•

Communications

• Redundancy
• I/O Scans
• Alarms
4.1

System Overview

4.1.1 Communications
As shown in Figure 7, the Genius Gateway (GCG001) sits on a PROFINET network which is
connected to a PROFINET Controller (PNC001, for instance). The PROFINET Controller is
mounted in an RX3i rack. This aspect of the architecture allows the RX3i to interact with the
GCG001.
The PROFINET network to which the GCG001 is connected operates at 100Mbps only. The
Network Speed will be set through auto-negotiation if necessary. Details of PROFINET
communications may be found in the PACSystems RX3i & RSTi-EP PROFINET I/O Controller
Manual GFK-2571.
The GCG001 is also connected to a Genius Bus. It takes the place of a traditional Genius Bus
Controller, meaning it can communicate with up to 31 other Genius Devices.
The Genius Bus operates as a Local Area Network (LAN) using twisted pair wiring. The wiring
is daisy-chained via the terminal strips on each device, as shown in Figure-10.
The Genius LAN will not be disrupted if power is lost on one its networked devices, since the
wiring passes through each device without requiring any active electronics to be present.
The LAN cabling must be terminated at both ends of the cable run, using resistors, the value
of which matches the impedance of the cable used in the application. See Figure 11 for
terminating the bus at the GCG001.
The Genius Bus can operate at several different baud rates. All devices on the bus must
operate at the same agreed baud rate. For further details, refer to the Genius I/O System
and Communications User's Manual, GEK-90486-1. The default baud rate of the GCG001,
when shipped from the factory is 153.6 kBaud. This may be changed via the PME
configuration software.
In the event the baud rate needs to be changed, the following sequence is recommended:
1. Disconnect the GCG001 module from the Genius bus.
2. Change the baud rate to the new value on all Genius devices connected to that bus.
3. Cycle power to all Genius devices on which the baud rate has just been changed.
4. Use the HHM to verify the baud rate was successfully changed on each device.
5. Retry the above steps on any devices that failed to switch over to the new baud rate.
6. Using PME, configure the GCG001 module to operate at the new baud rate.
System Operation
System Operation
Chapter 4
Sep 2019
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