State Industries GFK-0827 manual Synchronized Hot Standby CPU Redundancy System Configuration

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for three consecutive Genius I/O bus scans, the outputs are then controlled by the Genius Bus Controller at serial bus address 30 (Genius Bus Controller in the Secondary PLC).

If output data is not available from either bus address 31 or 30, the outputs go to their configured default (OFF or hold last state). The PLC at serial bus address 31 always has priority, therefore when the PLC with serial bus address 31 is On-line, it always has control of the outputs.

The redundancy system configuration is shown in the following figure. This example configuration shows only the redundancy system components. As described previously, a system can also contain Local I/O which is not a part of the redundancy scheme.

		PRIMARY UNIT					SECONDARY UNIT			a47001
P	C	B	R	G	P	C	B	R	G
S	P	T	C	B	S	P	T	C	B
	U	M	M	C		U	M	M	C
				31					30

* TERMINATED I/O CABLE

*TERMINATED I/O CABLE

other Genius devices

REMOTE DROP

B

B

B

P

S

I

I

I

I

I

I

I

I

L

L

L

S

C

O

O

O

O

O

O

O

O

O

O

O

A

C

C

C

N

K

K

K

N

E

R

Legend

PS	Power Supply	IC697PWRXXX
CPU	Central ProcessorUnit	IC697CPU780
BTM	Bus TransmitterModule	IC697BEM713
RCM	Redundancy Communications Module	IC697RCM711
GBC	Genius Bus Controller	IC697BEM731
BLOCK	GeniusI/OBlock	IC660XXXYYY
SCANNER	Remote I/O Scanner	IC697BEM733
*	TerminatedI/OCable	IC697CBL811/826

Figure 2. Synchronized Hot Standby CPU Redundancy System Configuration

6 Series 90-70 Hot Standby CPU Redundancy User's Guide ± December 1993 GFK-0827