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NORD Drivesystems BU0550 User Manual

Page 48

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PLC logic for NORD SK 54xE frequency inverters

48

BU 0550 GB-0813

3.5.1.8

TOF switch-off delay

If IN = TRUE is set, Q is set to TRUE. The timer starts if IN changes to FALSE. As long as the timer is
running (ET < PT) Q remains set to TRUE. The timer stops if (ET = PT) and Q then becomes FALSE. With
a new rising flank on IN, the timer ET is reset to zero.

Here, literals can be used for simplified input, e.g.

LD TIME#50s20ms

= 50.020 seconds

LD TIME#1d30m

= 1 day and 30 minutes

IN

Q

PT

ET

Table 66 TOF switch-off delay

NOTE

The time ET runs independently from the PLC cycle. Starting of the timer with IN and setting of
the output Q is only executed with the function call-up "CAL". The function call-up takes place
within a PLC cycle. However, with PLC programs which are longer than 5 ms this may result in
the occurrence of jitter.

VAR_INPUT

VAR_OUTPUT

Input

Explanation

Type

Output

Explanation

Type

IN

Timer active

BOOL

Q

TRUE

( ET

BOOL

PT

Duration

DINT

ET

Current timer reading

DINT