GE Industrial Solutions HE300GEN150 - Manual (Page 7)

PAGE 8 13 APR 2000 MAN0373-01
CH. 1
The physical nature of the Genius network can allow for great savings in wiring, as many discrete wires
can be replaced with a single communications cable. This allows tasks such as starting, stopping,
reversing, and changing speeds to be accomplished over the LAN. In addition, drive parameters and
diagnostic data previously not available to the PLC are easily accessible.
1.3 Genius Network Architecture
The Genius network architecture is depicted in Figure 1.1. Normally, a GE Fanuc programmable
controller runs the network through a PLC module called a Genius Bus Controller (GBC). Up to 32
devices are wired in a daisy chained fashion. Network devices support four communications terminals,
Serial 1, Serial 2, Shield In and Shield Out. The network is terminated at each end with an appropriate
terminating resistor.
Each device on the network (up to 32 devices) is assigned a Genius Bus Address ranging from 0 to 31.
Bus Controllers are typically assigned a Genius Bus Address of 31. In applications with redundant bus
controllers, the backup bus controller is address 30. Bus address 0 is normally reserved for the Genius
Hand Held Monitor.
Among other tasks, the bus controller allows Genius I/O (including the drives) on the network to be
mapped into PLC memory, monitoring inputs and controlling outputs. Intelligent, data intensive Genius
devices also share their data with the PLC through communications with the bus controller.
1.4 Genius Communications Services
The option card allows the drive to reside directly on the Genius LAN providing drive control and data
access capabilities to the PLC. There are three types of communications that can occur on the Genius
LAN. These are I/O Services, Global Data, and Datagrams. The option card supports all three of these
communications types.
1.4.1 I/O Service
I/O Service is the manner in which data is transferred to and from Genius I/O Blocks. Outputs are
selectively written to each I/O block from the CPU bus controller during each scan. The outputs written by
the CPU bus controller to the AF-300 drives include start/stop, fwd/rev, frequency (speed), fault reset, and
other outputs. Many I/O blocks also broadcast inputs to the bus every bus scan. The AF-300 does not
support this means of communication as it broadcasts its inputs (feedback) as Global Data.
1.4.2 Global Data
Global data is data broadcast over the network at large, with no particular destination. Each Genius
device has the capacity to broadcast up to 128 bytes of global data. Intelligent devices, which reside on
the LAN (bus controllers, OIUs, etc.), can read this data off the network. These devices are intelligent
and are able to interpret the data, which differs from Genius device to Genius device. The option card
utilizes global data to broadcast drive feedback data over Genius. Drive feedback data consists of
parameters such as speed reference, torque, current, faults, and function settings.
The option card allows the system designer to select which data is broadcast by the drive as global data.
This is important for two reasons. First, the data, which is desired to be monitored on a regular basis
varies from application to application. Second, the amount of global data broadcast by the drive is
directly proportional to response time. The ability to control the amount and content of global data output
is a vital feature of the option card.