SF_ModeSelector

Tip

The version of the function block as described here corresponds to the latest version of the function block in Version list of function blocks.

Applicable safety standards

SF_ModeSelector is a certified PLCopen function block. For detailed information about applied standards, see "PLCopen – Technical Committee 5 – Safety Software".

Important

The requirements listed in the standards must be fulfilled by the user.

Interface description

This function block selects the system operation mode, such as manual, automatic, semi-automatic, etc.

Name	Data Type	Initial Value	Description, parameter values
`Activate`	`BOOL`	`FALSE`	General input parameters
`S_Mode0`	`SAFEBOOL`	`FALSE`	Variable or constant. Input `0` of the mode selection switch `FALSE`: Mode 0 is not requested by the operator `TRUE`: Mode 0 is requested by the operator.
`S_Mode1`	`SAFEBOOL`	`FALSE`	Variable or constant. Input 0 of the mode selection switch `FALSE`: Mode 1 is not requested by the operator `TRUE`: Mode 1 is requested by the operator.
`S_Mode2`	`SAFEBOOL`	`FALSE`	Variable or constant. Input `2` of the mode selection switch `FALSE`: Mode 2 is not requested by the operator `TRUE`: Mode 2 is requested by the operator.
`S_Mode3`	`SAFEBOOL`	`FALSE`	Variable or constant. Input `3` of the mode selection switch `FALSE`: Mode 3 is not requested by the operator `TRUE`: Mode 3 is requested by the operator.
`S_Mode4`	`SAFEBOOL`	`FALSE`	Variable or constant. Input `4` of the mode selection switch `FALSE`: Mode 4 is not requested by the operator `TRUE`: Mode 4 is requested by the operator.
`S_Mode5`	`SAFEBOOL`	`FALSE`	Variable or constant. Input `5` of the mode selection switch `FALSE`: Mode 5 is not requested by the operator `TRUE`: Mode 5 is requested by the operator.
`S_Mode6`	`SAFEBOOL`	`FALSE`	Variable or constant. Input `6` of the mode selection switch `FALSE`: Mode 6 is not requested by the operator `TRUE`: Mode 6 is requested by the operator.
`S_Mode7`	`SAFEBOOL`	`FALSE`	Variable or constant. Input `7` of the mode selection switch `FALSE`: Mode 7 is not requested by the operator `TRUE`: Mode 7 is requested by the operator.
`S_Unlock`	`SAFEBOOL`	`FALSE`	Variable or constant. Locks the selected mode. `FALSE`: The current `S_ModeXSel` output is locked, and therefore a change of any `S_ModeX` input does not lead to a change at the `S_ModeXSel` output, even in the case of a rising edge of the Set mode. `TRUE`: The selected `S_ModeXSel` is not locked; a change of the mode selection is possible
`S_SetMode`	`SAFEBOOL`	`FALSE`	Variable (or constant `FALSE`, in case `AutoSetMode = TRUE`) Sets the selected mode. Operator confirms the setting of a mode. Any change to a new `S_ModeX = TRUE` leads to `S_AnyModeSel/S_ModeXSel = FALSE`, only a rising `SetMode` trigger edge will then result in a new `S_ModeXSel = TRUE`.
`AutoSetMode`	`BOOL`	`FALSE`	Constant Parameterizes the confirmation mode. `FALSE`: A change of mode must be confirmed by the operator via `SetMode`. `TRUE`: A valid change of the `S_ModeX` input to another `S_ModeX` automatically leads to `S_ModeXSel` without operator confirmation via `SetMode` (as long as it is not locked by `S_Unlock`).
`ModeMonitorTime`	`TIME`	`T#0`	Constant Maximum time allowed for changing the selection input. The `ModeMonitorTime` caution note must be observed.
`Reset`	`BOOL`	`FALSE`	General input parameters

ModeMonitorTime

For developers in Extended Level: The ModeMonitorTime input has to be set to a constant value. This means that the value must not be changed for the calls.

Table 24. VAR_OUTPUT

Name	Data Type	Initial Value	Description, parameter values
`Ready`	`SAFEBOOL`	`FALSE`	General output parameters
`S_Mode0Sel`	`SAFEBOOL`	`FALSE`	Indicates that mode 0 is selected and confirmed. `FALSE`: Mode 0 is not selected or not active. `TRUE`: Mode 0 is selected and active.
`S_Mode1Sel`	`SAFEBOOL`	`FALSE`	Indicates that mode 1 is selected and confirmed. `FALSE`: Mode 1 is not selected or not active. `TRUE`: Mode 1 is selected and active.
`S_Mode2Sel`	`SAFEBOOL`	`FALSE`	Indicates that mode 2 is selected and confirmed. `FALSE`: Mode 2 is not selected or not active. `TRUE`: Mode 2 is selected and active.
`S_Mode3Sel`	`SAFEBOOL`	`FALSE`	Indicates that mode 3 is selected and confirmed. `FALSE`: Mode 3 is not selected or not active. `TRUE`: Mode 3 is selected and active.
`S_Mode4Sel`	`SAFEBOOL`	`FALSE`	Indicates that mode 4 is selected and confirmed. `FALSE`: Mode 4 is not selected or not active. `TRUE`: Mode 4 is selected and active.
`S_Mode5Sel`	`SAFEBOOL`	`FALSE`	Indicates that mode 5 is selected and confirmed. `FALSE`: Mode 5 is not selected or not active. `TRUE`: Mode 5 is selected and active.
`S_Mode6Sel`	`SAFEBOOL`	`FALSE`	Indicates that mode 6 is selected and confirmed. `FALSE`: Mode 6 is not selected or not active. `TRUE`: Mode 6 is selected and active.
`S_Mode7Sel`	`SAFEBOOL`	`FALSE`	Indicates that mode 7 is selected and confirmed. `FALSE`: Mode 7 is not selected or not active. `TRUE`: Mode 7 is selected and active.
`S_AnyModeSel`	`SAFEBOOL`	`FALSE`	Indicates that one of the 8 modes is selected and confirmed. `FALSE`: No `S_ModeX` is selected. `TRUE`: One of the 8 `S_ModeX` is selected and active.
`Error`	`BOOL`	`FALSE`	General output parameters
`DiagCode`	`WORD`	`16#0000`	Diagnostic codes

Figure 58. Function block: SF_ModeSelector

Functional description

This function block block selects the system operation mode, such as manual, automatic, semi-automatic, etc. When starting the controller, it should be assumed that the machine is in a safe mode. When starting the machine, the transition to the mode set by the mode selector must be initiated by a device input (e.g. START button of the machine).

The activation of the FB following the default state is the ModeChanged state. This is also the safe state of the FB, where all S_ModeXSel and S_AnyModeSel are FALSE.

. When the FB is in the ModeChanged state:

The new S_ModeX input must be confirmed with a rising S_SetMode trigger edge (in case AutoSetMode = FALSE), which leads to a new S_ModeXSel output.
The new S_ModeX input automatically leads to an S_ModeXSel output (in case AutoSetMode = TRUE).
Such a transition from state 8005 to 8000 is valid only if one S_ModeX input is TRUE. As long as all S_ModeX are FALSE, the FB remains in state 8005, even if S_SetMode triggers.

The transition from ModeChanged to ModeSelected state, that is S_SetMode is set by the operator, is not monitored by a timer.

When the FB is in the ModeSelected state, the simultaneous occurrence of a new S_ModeX input (higher priority) and the NOT S_Unlock signal (lower priority) leads to the ModeChanged state.

The S_ModeX input parameters which are not used for mode selection should be assigned the default value FALSE to simplify the verification of the program.

Caution

The AutoSetMode input should be activated only if it is guaranteed that no hazard can occur when the S-PLC is started.

Status diagram

Figure 59. Status diagram: SF_Modeselector

Tip

Note: The transition from any state to the Idle state, initiated by Activate = FALSE, is not shown. In every case, these transitions have the highest priority.

Typical timing diagrams

Figure 60. Timing diagram 1: SF_ModeSelector

Figure 61. Timing diagram 2: SF_ModeSelector, error condition 2 for mode inputs

Figure 62. Timing diagram 3: SF_ModeSelector

Error detection

. The FB detects when none of the mode inputs is selected. This invalid condition is detected after the ModeMonitorTime expires:

Which restarts at each falling trigger edge of an S_ModeX input
Which is then in the ModeChanged state, which follows the activation of the FB.

In contrast, the FB directly detects whether or not more than one S_ModeX input is selected at the same time.

A static reset condition is detected when the FB is in either error state C001 or C002.

Error behavior

In the case of an error event, the S_ModeXSel and S_AnyModeSel outputs are set to the safe state (FALSE). The DiagCode input displays the relevant error code and the Error output is set to TRUE.

An error must be detected with the rising trigger edge of the Reset BOOL input. The FB switches from an Error state to the ModeChanged state.

FB-specific status and error codes

Table 25. FB-specific error codes

`DiagCode`	Statue Name	Status description and output setting
`16#C001`	`Error` `Short-circuit`	The FB detects that two or more `S_ModeX` are TRUE (for example, short-circuiting of lines). `Ready = TRUE` `Error = TRUE` `S_AnyModeSel = FALSE` All `S_ModeXSel = FALSE`
`16#C002`	`Error` `Open-circuit`	The FB detects that all `S_ModeX` are `FALSE`. The time interval following a falling `S_ModeX` trigger edge exceeds the ModeMonitorTime (for example, short-circuiting of lines) `Ready = TRUE` `Error = TRUE` `S_AnyModeSel = FALSE` All `S_ModeXSel = FALSE`
`16#C003`	`Reset Error 1`	Static reset signal detected in status `C001`. `Ready = TRUE` `Error = TRUE` `S_AnyModeSel = FALSE` All `S_ModeXSel = FALSE`
`16#C004`	`Reset Error 2`	Static reset signal detected in status `C002`. `Ready = TRUE` `Error = TRUE` `S_AnyModeSel = FALSE` All `S_ModeXSel = FALSE`

Table 26. FB-specific status codes (no error)

`DiagCode`	Statue Name	Status description and output setting
`16#0000`	`Idle`	The function block is not active (basic state). `Ready = FALSE` `Error = FALSE` `S_AnyModeSel = FALSE` All `S_ModeXSel = FALSE`
`16#8005`	`ModeChanged`	Status after activation or when `S_ModeX` has changed (except locked) or after reset of an error status `Ready = TRUE` `Error = FALSE` `S_AnyModeSel = FALSE` All `S_ModeXSel = FALSE`
`16#8000`	`ModeSelected`	Valid mode selection, but not yet locked. `Ready = TRUE` `Error = FALSE` `S_AnyModeSel = TRUE` `S_ModeXSel` = Selected `X` is `TRUE`; others are `FALSE`
`16#8004`	`ModeLocked`	Valid mode selection is locked. `Ready = TRUE` `Error = FALSE` `S_AnyModeSel = TRUE` `S_ModeXSel` = Selected `X` is `TRUE`; others are `FALSE`