FB_BA_SldgLmtMonit

Functional description

The function block can be used for sliding limit value monitoring. This may be function monitoring of a control valve through comparison of the command output and the position feedback.

Note that must not be greater than or equal to . If this is the case, = Lmt and = - 0.05. rHiLmt rLoLmt rOutHiLmt rHi rOutLoLmt rHiLmt

Diagram 1

Diagram 1

VAR_INPUT

bEn            : BOOL;
rX             : REAL;
rHiLmt         : REAL;
rLoLmt         : REAL;
udiTiDlyHiLmt  : UDINT;[s]
udiTiDlyLoLmt  : UDINT;[s]

bEn: Block enable

rX: Actual value

rHiLmt: Upper limit value. rOutHiLmt = rHiLmt

rLoLmt: Lower limit value. rOutLoLmt = rLoLmt

udiTiDlyHiLmt : If rX is greater than rOutHiLmt and the delay udiTiDlyHiLmt has elapsed, bQ is set, see diagram 1.

udiTiDlyLoLmt : If rX is less than rOutLoLmt and the delay udiTiDlyLoLmt has elapsed, bQ is set, see diagram 1.

VAR_OUTPUT

bQ               : BOOL;
rOutHiLmt        : REAL;
rOutLoLmt        : REAL;
udiRemTiDlyHiLmt : UDINT;[s]
udiRemTiDlyLoLmt : UDINT;[s]

bQ: limit value monitoring is enabled. bQ can only be reset via bEn = FALSE.

rOutHiLmt: output upper limit

rOutLoLmt : output lower limit

udiRemTiDlyHiLmt : delay countdown udiTiDlyHiLmt

udiRemTiDlyLoLmt : delay countdown udiTiDlyLoLmt

Requirements