Redundance8

Redundance8 (FB)

FUNCTION_BLOCK Redundance8

Short description

Redundant control of 0 - 8 identical devices Influencing factors: requests, operating hours, operating and fault conditions Typical application: determination of the master and follower devices

Representation

Interfaces

Inputs

Name	Data type	Value range	Initial value	Function
wTotalNumberOfDevices	WORD		2	Total number of devices (0 - cwMaxMumberOfDevices)
wActiveNumberOfDevices	WORD		0	Number of active devices (0 - wTotalNumberOfDevices)
xFb1	BOOL		FALSE	Running - Device 1 (TRUE = running)
xFb2	BOOL		FALSE	Running - Device 2 (TRUE = running)
xFb3	BOOL		FALSE	Running - Device 3 (TRUE = running)
xFb4	BOOL		FALSE	Running - Device 4 (TRUE = running)
xFb5	BOOL		FALSE	Running - Device 5 (TRUE = running)
xFb6	BOOL		FALSE	Running - Device 6 (TRUE = running)
xFb7	BOOL		FALSE	Running - Device 7 (TRUE = running)
xFb8	BOOL		FALSE	Running - Device 8 (TRUE = running)
xAlarm1	BOOL		TRUE	Fault - Device 1 (TRUE = fault)
xAlarm2	BOOL		TRUE	Fault - Device 2 (TRUE = fault)
xAlarm3	BOOL		TRUE	Fault - Device 3 (TRUE = fault)
xAlarm4	BOOL		TRUE	Fault - Device 4 (TRUE = fault)
xAlarm5	BOOL		TRUE	Fault - Device 5 (TRUE = fault)
xAlarm6	BOOL		TRUE	Fault - Device 6 (TRUE = fault)
xAlarm7	BOOL		TRUE	Fault - Device 7 (TRUE = fault)
xAlarm8	BOOL		TRUE	Fault - Device 8 (TRUE = fault)
uiOperatingHours1	UDINT		0	Operating hours - Device 1
uiOperatingHours2	UDINT		0	Operating hours - Device 2
uiOperatingHours3	UDINT		0	Operating hours - Device 3
uiOperatingHours4	UDINT		0	Operating hours - Device 4
uiOperatingHours5	UDINT		0	Operating hours - Device 5
uiOperatingHours6	UDINT		0	Operating hours - Device 6
uiOperatingHours7	UDINT		0	Operating hours - Device 7
uiOperatingHours8	UDINT		0	Operating hours - Device 8
xUpdate	BOOL			Trigger recalculation of the sequence on every rising edge

Outputs

Name	Data type	Value range	Initial value	Function
udiCurrentSequence	UDINT		0	Current device sequence as integer
sCurrentSequence	STRING		‘’	Current device sequence as string
wNumberOfOperationalDevices	WORD		0	Number of operational devices
xCmd1	BOOL		FALSE	Enable - Device 1 (TRUE = enable)
xCmd2	BOOL		FALSE	Enable - Device 2 (TRUE = enable)
xCmd3	BOOL		FALSE	Enable - Device 3 (TRUE = enable)
xCmd4	BOOL		FALSE	Enable - Device 4 (TRUE = enable)
xCmd5	BOOL		FALSE	Enable - Device 5 (TRUE = enable)
xCmd6	BOOL		FALSE	Enable - Device 6 (TRUE = enable)
xCmd7	BOOL		FALSE	Enable - Device 7 (TRUE = enable)
xCmd8	BOOL		FALSE	Enable - Device 8 (TRUE = enable)
wPrio1	WORD		0	Current priority of device 1 (0 = none, 1 - wTotalNumberOfDevices)
wPrio2	WORD		0	Current priority of device 2 (0 = none, 1 - wTotalNumberOfDevices)
wPrio3	WORD		0	Current priority of device 3 (0 = none, 1 - wTotalNumberOfDevices)
wPrio4	WORD		0	Current priority of device 4 (0 = none, 1 - wTotalNumberOfDevices)
wPrio5	WORD		0	Current priority of device 5 (0 = none, 1 - wTotalNumberOfDevices)
wPrio6	WORD		0	Current priority of device 6 (0 = none, 1 - wTotalNumberOfDevices)
wPrio7	WORD		0	Current priority of device 7 (0 = none, 1 - wTotalNumberOfDevices)
wPrio8	WORD		0	Current priority of device 8 (0 = none, 1 - wTotalNumberOfDevices)
xErr	BOOL		FALSE	Output - Fault
eOperationalCondition	eRedundance3_OperationalMode			Number / name of the current operating condition

Setpoints / parameters

Name	Data type	Value range	Initial value	Function
xConOperatingHours	BOOL		TRUE	FALSE = follow switching enabled only by input xUpdate, TRUE = follow switching automatically by operating hours
xEnFb	BOOL		TRUE	FALSE = switching by enable (xCmdX), TRUE = switching by running signal (xFbX)
wTolerance	WORD		100	Threshold - operating hours difference for direct follow change in partial load operation

Function description

General

This function block is used for redundant control of 0 - 8 identical devices depending on the influencing variables. Demands (wActiveNumberOfDevices), operating hours (uiOperatingHours), operating states (xFb) and fault states (xAlarm).

Input wTotalNumberOfDevices

This input is used to determine the total number of available devices. Devices are assigned consecutively starting from the lowest device numbers. Example: wTotalNumberOfDevices = 3: Devices 1 - 3 (inputs and outputs) are used / considered. Allowed range: 0 - cwMaxNumberOfDevices

Input wActiveNumberOfDevices

This input is used to determine the number of devices that should currently be used. Allowed range: 0 - wTotalNumberOfDevices

Input xUpdate

Each rising edge on this input triggers a recalculation of the current device sequence. Boundary conditions: xConOperationHours = FALSE, operating hours difference = 0 hours.

Output udiCurrentSequence

This output always shows the current device sequence as an integer. The number of the device with the highest priority is always at the beginning, followed by the number of the device with the second highest priority, etc. Example: udiCurrentSequence = 145 means: Device 1 = priority 1, Device 4 = priority 2 and Device 5 = priority 3

Output sCurrentSequence

This output always shows the current device sequence as a string with delimiters. The same applies regarding priorities as for the output udiCurrentSequence. Example: sdiCurrentSequence = ‘1-4-5’ means: Device 1 = priority 1, Device 4 = priority 2 and Device 5 = priority 3

Output wNumberOfOperationalDevices

This output always indicates the number of operational devices.

Output Fault xErr

This output is active (= TRUE) if at least one of the following conditions is met.

1. wActiveNumberOfDevices > wTotalNumberOfDevices

2. wTotalNumberOfDevices > cwMaxNumberOfDevices

3. wActiveNumberOfDevices > wOperationalNumberofDevices

In all other cases the output *xErr* is not active (= FALSE).

Output eOperationalCondition

This output always represents the current load situation (idle, partial load, full load) depending on the setpoint / parameter xEnFb thereof. xEnFb = FALSE: The enable outputs xCmd of the operational devices are evaluated / considered. xEnFb = TRUE: The operating states xFb of the operational devices are evaluated / considered. Example: xEnFb = TRUE, wTotalNumberOfDevices = 3 and xFb1 = TRUE and xFb2 = TRUE: Output = PartLoad_Inputs_Fb

Setpoint / parameters xConOperatingHours

xConOperatingHours = FALSE: Switching of the device sequence is triggered only by a rising edge at input xUpdate . xConOperatingHours = TRUE: Switching of the device sequence is triggered depending on the operating hours, the running signals (when xEnFb = TRUE) and the enables (when xEnFb = FALSE) .

Setpoint / parameters xEnFb

xEnFb = FALSE: The enable outputs ‘xCmd’ of the operational devices are evaluated / considered. xEnFb = TRUE: The running states ‘xFb’ of the operational devices are evaluated / considered.

Setpoint / parameters wTolerance

This setpoint determines the maximum operating hours difference before switching the device sequence due to operating hours.

Determination of the device sequence

A change of the device sequence can in general only occur if at least one of the following conditions is met:

1. The fault condition of at least one device ( devices 1 - wTotalNumberOfDevices ) has changed (high priority)

2. The total number of devices (input wTotalNumberOfDevices) (1 - cwMaxNumberOfDevices) has changed (high priority)

3. The operating hours of at least one operational device (devices 1 - wTotalNumberOfDevices) have changed (low priority)

Definition - idle:

xEnFb = FALSE: The enable outputs ‘xCmd’ of all operational devices (devices 1 - wTotalNumberOfDevices) are inactive (= FALSE) xEnFb = TRUE: The running signals ‘xFb’ of all operational devices (devices 1 - wTotalNumberOfDevices) are inactive (= FALSE)

Definition - full load:

xEnFb = FALSE: The enable outputs ‘xCmd’ of all operational devices (devices 1 - wTotalNumberOfDevices) are active (= TRUE) xEnFb = TRUE: The running signals ‘xFb’ of all operational devices (devices 1 - wTotalNumberOfDevices) are active (= TRUE)

Definition - partial load:

xEnFb = FALSE: The number of enable outputs 'xCmd' of all operational devices in state active (= TRUE) is greater than or equal to 1 and less than the number of all operational devices (devices 1 - wTotalNumberOfDevices) xEnFb = FALSE: The number of status feedbacks xFb of all operational devices in state active (= TRUE) is greater than or equal to 1 and less than the number of all operational devices (devices 1 - wTotalNumberOfDevices) Switching with high priority (= immediate) depending on the fault conditions (inputs xAlarm) and the input wTotalNumberOfDevices. The fault condition of each device in the range 1 - wTotalNumberOfDevices is sampled cyclically and evaluated for changes. The input wTotalNumberOfDevices is cyclically detected and evaluated for changes. Each faulty device (input xAlarm = TRUE) in the range 1 - wTotalNumberOfDevices is no longer operational. Any change in the fault state of at least one device in the range 1 - wTotalNumberOfDevices triggers an immediate recalculation of the device sequence. Any change on the input wTotalNumberOfDevices triggers an immediate recalculation of the device sequence. Switching with lower priority depending on operating hours (inputs udiOperationHours), operating states (inputs xFb) and enable outputs (outputs xCmd) of devices 1 - 3. The operating hours of each operational device in the range 1 - wTotalNumberOfDevices are sampled cyclically and evaluated for changes. The operating states and enable outputs of each operational device in the range 1 - wTotalNumberOfDevices are sampled cyclically. Recalculation of the device sequence occurs as soon as one of the situations described below applies: Situation 1 (xConOperationHours = FALSE, rising edge at input xUpdate) A recalculation of the device sequence takes place with an operating hours difference of 0 hours, i.e. the non-faulty device with the lowest operating hours has the highest priority (in case of equal operating hours the device with the lower number has the higher priority). Situation 2 (xConOperationHours = TRUE, idle or full load) In idle or full load a recalculation of the device sequence takes place with an operating hours difference of 0 hours, i.e. the non-faulty device with the lowest operating hours has the highest priority (in case of equal operating hours the device with the lower number has the higher priority). The recalculation of the device sequence is triggered if the operating hours of at least one operational device have changed. Situation 3 (xConOperationHours = TRUE, partial load) On the first transition into partial load operation a recalculation of the device sequence takes place with an operating hours difference of 0 hours, i.e. the non-faulty device with the lowest operating hours has the highest priority (in case of equal operating hours the device with the lower number has the higher priority). In regular partial load operation a recalculation of the device sequence takes place with an operating hours difference of wTolerance hours. The recalculation of the device sequence is triggered if the operating hours of at least one operational device have changed.

Enable outputs 'xCmd’

The states of the outputs of the devices in the range 1 - wTotalNumberOfDevices are finally determined as follows: The enable outputs of the operational devices in the range 1 - wTotalNumberOfDevices are activated if their current priority <= the number of requested devices (input *wActiveNumberOfDevices). The enable outputs of the operational devices in the range 1 - wTotalNumberOfDevices are deactivated if their current priority > the number of requested devices (input wActiveNumberOfDevices).

Priority outputs wPrio

The priority outputs of each device always contain the current priority in the range 0 - wTotalNumberOfDevices. Priority = 0: The device has no or an invalid priority Priority = 1: The device has the highest priority Priority = 2: The device has the second highest priority Priority = 3: The device has the third highest priority etc.

CODESYS

InOut:

Scope	Name	Type	Initial
Input	wTotalNumberOfDevices	WORD	2
Input	wActiveNumberOfDevices	WORD	0
Input	xFb1	BOOL	FALSE
Input	xFb2	BOOL	FALSE
Input	xFb3	BOOL	FALSE
Input	xFb4	BOOL	FALSE
Input	xFb5	BOOL	FALSE
Input	xFb6	BOOL	FALSE
Input	xFb7	BOOL	FALSE
Input	xFb8	BOOL	FALSE
Input	xAlarm1	BOOL	TRUE
Input	xAlarm2	BOOL	TRUE
Input	xAlarm3	BOOL	TRUE
Input	xAlarm4	BOOL	TRUE
Input	xAlarm5	BOOL	TRUE
Input	xAlarm6	BOOL	TRUE
Input	xAlarm7	BOOL	TRUE
Input	xAlarm8	BOOL	TRUE
Input	udiOperatingHours1	UDINT	0
Input	udiOperatingHours2	UDINT	0
Input	udiOperatingHours3	UDINT	0
Input	udiOperatingHours4	UDINT	0
Input	udiOperatingHours5	UDINT	0
Input	udiOperatingHours6	UDINT	0
Input	udiOperatingHours7	UDINT	0
Input	udiOperatingHours8	UDINT	0
Input	xUpdate	BOOL
Input Const	xConOperatingHours	BOOL	TRUE
Input Const	xEnFb	BOOL	TRUE
Input Const	wTolerance	WORD	100
Output	udiCurrentSequence	UDINT	0
Output	sCurrentSequence	STRING	‘’
Output	wNumberOfOperationalDevices	WORD	0
Output	xCmd1	BOOL	FALSE
Output	xCmd2	BOOL	FALSE
Output	xCmd3	BOOL	FALSE
Output	xCmd4	BOOL	FALSE
Output	xCmd5	BOOL	FALSE
Output	xCmd6	BOOL	FALSE
Output	xCmd7	BOOL	FALSE
Output	xCmd8	BOOL	FALSE
Output	wPrio1	WORD	0
Output	wPrio2	WORD	0
Output	wPrio3	WORD	0
Output	wPrio4	WORD	0
Output	wPrio5	WORD	0
Output	wPrio6	WORD	0
Output	wPrio7	WORD	0
Output	wPrio8	WORD	0
Output	xErr	BOOL	FALSE
Output	eOperationalCondition	eRedundance3_OperationalMode