GE GFK0579B ユーザーズマニュアル
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Chapter 1 Introduction
Genius Bus
The Genius bus is an industrially–hardened Local–Area–Network (LAN). It passes
I/O (control) data and background information (datagrams) between the Remote I/O
Scanner and a Genius bus controller. The communicated data is protected from
environmental interference and corruption in several ways. Each byte is
triply–encoded during transmission, and each message is checksummed with a cyclic
redundancy check (CRC). Embedded intelligence at either end also checks for correct
message length and type.
I/O (control) data and background information (datagrams) between the Remote I/O
Scanner and a Genius bus controller. The communicated data is protected from
environmental interference and corruption in several ways. Each byte is
triply–encoded during transmission, and each message is checksummed with a cyclic
redundancy check (CRC). Embedded intelligence at either end also checks for correct
message length and type.
A Genius bus can support up to 32 devices. Each remote drop counts as one device on
the bus, regardless of the number or type of modules it includes. A bus can serve any
mix of remote drops, I/O blocks, Bus Controllers and Hand–held Monitors, provided
the bus scan time does not exceed 400mS. Typical busses reserve one location for a Bus
Controller and one for a Hand–held Monitor, leaving 30 for additional devices. The
illustration below shows a Bus Controller in a Series 90–70 PLC connected to a Genius
bus with I/O blocks and two single–rack remote drops.
the bus, regardless of the number or type of modules it includes. A bus can serve any
mix of remote drops, I/O blocks, Bus Controllers and Hand–held Monitors, provided
the bus scan time does not exceed 400mS. Typical busses reserve one location for a Bus
Controller and one for a Hand–held Monitor, leaving 30 for additional devices. The
illustration below shows a Bus Controller in a Series 90–70 PLC connected to a Genius
bus with I/O blocks and two single–rack remote drops.
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90–70 REMOTE RACK
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MAXIMUM BUS LENGTH
7500 FEET WITH 16 DEVICES, AT 38.6K BAUD
3500 FEET WITH 32 DEVICES, AT 153.6K BAUD EXT.
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90–70 REMOTE RACK
Bus Type
Daisy–chained bus cable; single twisted pair plus shield or Twinax.
Fiber optics cable and modems can also be used.
Fiber optics cable and modems can also be used.
Bus Termination
75, 100, 120, or 150 ohm resistor at both ends of electrical bus cable.
Baud Rate
Configurable. 153.6 Kbaud standard, 153.6 Kbaud extended,
76.8Kbaud, or 38.4 Kbaud.
76.8Kbaud, or 38.4 Kbaud.
Maximum Bus
Length
Length
7500 feet at 38.4 Kbaud, 4500 feet at 76.8 Kbaud, 3500feet at 153.6
Kbaud extended, 2000 feet at 153.6 Kbaud, standard. Maximum
length at each baud rate also depends on cable type. The Genius I/O
System User’s Manual pro vides a complete list of cable types, show-
ing corresponding bus lengths and baud rates. Greater bus lengths
are possible using sections of fiber optics cable with modems.
Kbaud extended, 2000 feet at 153.6 Kbaud, standard. Maximum
length at each baud rate also depends on cable type. The Genius I/O
System User’s Manual pro vides a complete list of cable types, show-
ing corresponding bus lengths and baud rates. Greater bus lengths
are possible using sections of fiber optics cable with modems.
Maximum Number of
Devices
Devices
32 devices at 153.6 Kbaud standard, 153.6 Kbaud extended, or 76.8
Kbaud. 16 devices at 38.4 Kbaud. Includes Bus Controller and
Hand– held Monitor.
Kbaud. 16 devices at 38.4 Kbaud. Includes Bus Controller and
Hand– held Monitor.