State Industries GFK-0827 manual RedundancyOptions, Plc

A

Table 13. RedundancyOptions

						Output
Option	Key	PLC	Scan	Data	I/O System	Selection	Redund.	Redund.	SelectionGuide
			Sync	Sync		Method	Bus	I/O
	1A	290-70s	no	Application	90-70	Hot	yes - 2	no	Higher Density Analog Inputs
				Logic [	(I/OScanner)	Standby
Hot Standby	1B	290-70s	no	Application	90-30	Hot	yes - 2	no	MorecompetitiveI/O
				Logic [	(GCM+)	Standby
Application	1C	290-70s	no	Application	GeniusI/O	Hot	yes - 2	no	Highly distributable with diagnos-
				Logic [		Standby			tics. Thermocouple. RTD
	1D	290-70s	no	Application	90-30	Hot	yes - 2	no	Least expensive. Limited to
				Logic [	(GCM+)	Standby			512 Inputs, 512 Outputs
Hot Standby	2	290-70s	yes	Operating	90-30	Hot	yes - 2	no	Redundant Bus Applications.
Product plus				System	(GCM+)	Standby			MorecompetitiveI/O.
ApplicationLogic				Function
	3A	290-70s	yes	Operating	90-70	Hot	no	no	Higher Density Analog Inputs
				System	(I/OScanner)	Standby
Hot Standby Product	3B	290-70s	yes	Operating	90-30	Hot	no	no	MorecompetitiveI/O.
				System	(GCM+)	Standby
	3C	290-70s	yes	Operating	GeniusI/O	Hot	no	no	Highly Distributable with diagnos-
				System		Standby			tics. Thermocouple. RTD.
ESD Duplex	4	290-70s	no	no	GeniusI/O	Duplex	yes - 2	yes	For Fail-Safe ESD applications.
ApplicationLogic
ESD Duplex	5A	290-70s	no	no	GeniusI/O	GMR	yes - 2	yes	For Fail±Safe or fault tolerant ESD
GMR Product							or 3		applications.
ESD Triplex	5B	390-70s	no	no	GeniusI/O	GMR	yes - 3	yes	For fault tolerant ESD applications.
GMR Product

[See list of restrictions below.

Explanation of terms used in the above Table of Redundancy Options.

Hot Standby Redundancy	Two CPUs are connected to one or more I/O. One CPU is active; the other is in standby. If the active
	unit fails, the standby unit takes control of the process (Hot Standby Redundancy is sometimes
	known as Hot Backup Redundancy).
Scan Synchronization	Scan mechanisms may be synchronized to keep active and standby units in lockstep to minimize
	ºbumpsº or upsets to the process when switching from active to standby unit.
Data Synchronization	Keeps standby unit refreshed with the current state of the active unit to minimize ºbumpsº or upsets
	to the process when switching from active to standby unit.
Emergency Shutdown System (ESD)	Two or three unsynchronized CPUs solve logic asynchronously based on common inputs. Output
	state is voted on by the output devices. The inputs and outputs are normally energized and do not
	change state. DUPLEX ESD is Failsafe while TRIPLEX ESD is fault tolerant.
ApplicationLogic-BasedSolutions	Has many restrictions (see the list of restrictions on page 13).
ProductSolutions	Has functions built into the operating system that make the system easier to engineer and more
	robust. Product solutions are preferable to application solutions from a support perspective.
Output Selection Method	Refers to the algorithm in the I/O device, such as Hot Standby, Duplex, or No Redundancy Modes.
	These modes may refer to existing Genius I/O terminology. GMR (Genius Modular Redundancy)
	mode is a voting algorithm available in Genius I/O DC blocks.
FailSafe	An ESD system will fail such that the process under supervision will be shutdown.
Fault Tolerant	In an ESD system any single failure will not disrupt the process under supervision.

GFK-0827 Appendix A Redundancy Alternatives 87