SAMPLETM: Sample time

Function description

With this function block the function blocks of the control mechanism are released under time control.

To control, the Q output of the SAMPLETM function block is connected with the input of the function block to be controlled.

The Q output is activated for one program cycle after the stated time at the INTERVAL input has expired.

The DELSCAN input was created to prevent the simultaneous start of more than one sample time dependent FFB which are controlled by various SAMPLETM function blocks. At this input the number of cycles is stated according to which the activation of Q after a cold start is delayed. Therefore it is possible to release sample time dependent function blocks step by step to reduce the load on the CPU during the start cycle.

and can be configured as additional parameters.

Representation in FBD

Representation:

Representation in LD

Representation:

Representation in IL

Representation:

CAL SAMPLETM_Instance (INTERVAL:=ScanTime, 
    DELSCAN:=NoOfDelayCycles, Q=>Enable)

Representation in ST

Representation:

SAMPLETM_Instance (INTERVAL:=ScanTime, 
    DELSCAN:=NoOfDelayCycles, Q=>Enable) ;

Parameter description

Description of input parameters:

Parameter	Data type	Description
INTERVAL	TIME	Sample time for connected control mechanism function block
DELSCAN	INT	Number of delay cycles after a cold start

Description of output parameters:

Parameter	Data type	Description
Q	BOOL	Release of control mechanism function block

Runtime error

For a list of all block error codes and values, see Controller.

EN stands for ENable; it is an optional block input. When the EN input is enabled, an ENO output is set automatically.

If EN = 0, the block is not enabled; its internal program is not executed, and ENO is set to 0.

If EN = 1, the block's internal program is run and ENO is set to 1. If an error occurs, ENO is set to 0.

If the EN input is not connected, it is set automatically to 1.

ENO

ENO stands for Error NOtification; this is the output associated with the optional input EN.

If ENO is set to 0 (because EN = 0 or in case of an execution error):

the status of the function block outputs remains the same as it was during the previous scanning cycle that executed correctly;
the output(s) of the function, as well as the procedures, are set to "0".

TIME

The TIME type expresses a time in milliseconds. Encoded in 32 bits, this type can be used to obtain times from 0 to 2 32-1 milliseconds.

The TIME type has the following units: days (d), hours (h), minutes (m), seconds (s) and milliseconds (ms). A literal value of type TIME is represented by a combination of the preceding types prefixed with T#, t#, TIME# or time#.

Examples: T#25h15m, t#14,7S, TIME#5d10h23m45s3ms