ReadNbrSlaves (FB)¶

FUNCTION_BLOCK ReadNbrSlaves EXTENDS ETrigA

Reads the number of connected slaves

Example:

PROGRAM PLC_PRG
VAR
   readnbr : ReadNbrSlaves;
   xRead : BOOL;
   wNbrSlaves : WORD;
END_VAR

IF xRead THEN
   readnbr.usiCom := DWORD_TO_USINT(Ethercat_Master.InstanceNumber);
   readnbr(xExecute := TRUE, udiTimeOut := 1000);
   IF readnbr.xDone THEN
      xRead := FALSE;
      wNbrSlaves := readnbr.wNumberSlaves;
      readnbr(xExecute := FALSE);
    END_IF
 END_IF

InOut:

Scope	Name	Type	Initial	Comment	Inherited from
Input	`xExecute`	`BOOL`		Rising edge: Action starts Falling edge: Resets outputs If a falling edge occurs before the function block has completed its action, the outputs operate in the usual manner and are only reset if either the action is completed or in the event of an error. In this case, the corresponding output values (`xDone`, `xError`, `iError`) are present at the outputs for exactly one cycle.	ETrigA
Input	`xAbort`	`BOOL`		`TRUE`: Action is stopped immediately and all outputs are reset to their initial values.	ETrigA
Output	`xDone`	`BOOL`		`TRUE`: Action successfully completed	ETrigA
	`xBusy`	`BOOL`		`TRUE`: Function block active	ETrigA
	`xError`	`BOOL`		`TRUE`: Error occurred, function block aborts action `FALSE`: No error	ETrigA
	`xAborted`	`BOOL`		`TRUE` : Action aborted by user	ETrigA
Input	`usiCom`	`USINT`	1	index of master 1: first Ethercat master
Input	`udiTimeOut`	`UDINT`		Timeout for operation in ms
Output	`wNumberSlaves`	`WORD`		number of slaves currently available