FB_MODE

Description Function Block

The FB_MODE function block can be used to implement operating mode selector switches. The function block has 8 inputs and 8 outputs which are looped through one-to-one, whereby up to 8 different operating modes can be selected. The FB_MODE sets the corresponding output only if exactly one input is set ("1"), whereby the other outputs remain in the safe state ("0"). If no input is set or if more than one is set, then all outputs are in the safe state.

The bRestart input of the FB can be activated (active or manual restart) by linking the input. An open bRestart input will create a compiler error. If the restart is supposed to be executed automatically (non-active or automatic restart), then the bRestart input must be deleted. If the bRestart input is activated, then the safe state of the outputs is quit only via a 0->1->0 signal sequence at the Restart input at the start and when changing the operating mode. Furthermore, a discrepancy time can be specified at the tDiscTime input which is used to monitor the change from one operating mode to the next.

Tip

At least two inputs of FB_MODE must be connected.

Table 18. VAR_INPUT

Name	Data Type	Initial Value	Description, Parameter Values
`bRestart`	`SAFEBOOL`	`FALSE`	When the FB is started or when all outputs have been switched to the safe state, the signal sequence 0->1->0 must be recognized at the restart input before the safe state of the outputs is canceled.
`bOpIn1`	`SAFEBOOL`	`FALSE`	1st input channel
`bOpIn2`	`SAFEBOOL`	`FALSE`	2nd input channel
`bOpIn3`	`SAFEBOOL`	`FALSE`	3rd input channel
`bOpIn4`	`SAFEBOOL`	`FALSE`	4th input channel
`bOpIn5`	`SAFEBOOL`	`FALSE`	5th input channel
`bOpIn6`	`SAFEBOOL`	`FALSE`	6th input channel
`bOpIn7`	`SAFEBOOL`	`FALSE`	7th input channel
`bOpIn8`	`SAFEBOOL`	`FALSE`	8th input channel
`tDiscTime`	`SAFETIME`	`TIME#0ms`	Discrepancy monitoring time

Table 19. VAR_OUTPUT

Name	Data Type	Initial Value	Description, Parameter Values
`bOpOut1`	`SAFEBOOL`	`FALSE`	1st output channel
`bOpOut2`	`SAFEBOOL`	`FALSE`	2nd output channel
`bOpOut3`	`SAFEBOOL`	`FALSE`	3rd output channel
`bOpOut4`	`SAFEBOOL`	`FALSE`	4th output channel
`bOpOut5`	`SAFEBOOL`	`FALSE`	5th output channel
`bOpOut6`	`SAFEBOOL`	`FALSE`	6th output channel
`bOpOut7`	`SAFEBOOL`	`FALSE`	7th output channel
`bOpOut8`	`SAFEBOOL`	`FALSE`	8th output channel
`bError`	`SAFEBOOL`	`FALSE`	`TRUE`: The discrepancy time monitoring or the input monitoring has detected an error. The error must be acknowledged via the `ERR_ACK` input of the associated POU (TwinSAFE group). `FALSE`: No error was detected.