FB_BA_SwiMonit

Functional description

The function block monitors a limit switch in two steps.
Step 1 includes monitoring while the actuator is moving.
Step 2 includes monitoring of the opened state of the actuator.

The function is activated via the input bEn. If bEn is FALSE, the outputs bErrOpn/bErrSwi are also FALSE.

Step 1: If the input bIn is TRUE, the move time for the actuator udiTiAct/udiRT_TiAct is started. If the input bSwi does not become TRUE within this time, a fault is displayed via output bErrOpn. If bSwi becomes TRUE within the time udiTiAct, step 1 is complete, and step 2 becomes active.

Step 2: bIn and bSwi are TRUE. If bIn becomes FALSE, step 1 becomes active again. If bSwi becomes FALSE and does not become TRUE again within the time udiTiDlyMonitSwi/udiRT_TiDlyMonitSwi, a fault is displayed via output bErrSwi.

The faults bErrOpn/bErrSwi are reset, if either bEn or bIn are FALSE.

VAR_INPUT

bEn               : BOOL;
bIn               : BOOL;
bSwi              : BOOL;
udiTiAct          : UDINT;
udiTiDlyMonitSwi  : UDINT;

bEn: a TRUE signal at this input activates the function block. The value at input udiVall is only output with a delay at udiValQ. If bEn is FALSE, the input value udiValI is output without delay.

bIn: the actuator control must be applied at this input.

bSwi: limit switch actuator

udiTiAct: actuator stroke time [s]

udiTiDlyMonitSwi: delay time of a limit switch in open state [s]. The time becomes active, if bIn is TRUE and the limit switch bSwi changes its state from TRUE to FALSE.

VAR_OUTPUT

bErrOpn              : BOOL;
bErrSwi              : BOOL;
udiRT_TiAct          : UDINT;
udiRT_TiDlyMonitSwi  : UDINT;

bErrOpn: fault step 1; limit switch has not reached its end position during the procedure

bErrSwi: fault step 2; limit switch or actuator has left its end position in opened state

udiRT_TiAct: countdown for setting the output bErrOpn [s]. The preset originates from udiTiAct.

udiRT_TiDlyMonitSwi: countdown for setting the output bErrSwi [s]. The preset originates from udiTiDlyMonitSwi.

Requirements