Short description
The edge of an input pulse triggers a configurable time. The output is reset when this time has expired. An off warning can be output prior to the expiration of this time.
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Connection |
Description |
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Input Trg |
You trigger the time (off-delay) for the stairway switch with a signal at input Trg (Trigger). |
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Parameter |
T : The output is reset (1 to 0 transition) when the off-delay time T has expired.
T
! : determines the triggering time for the prewarning. |
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Output Q |
Q is reset after the time T has expired. A warning signal can be output before this time has expired. |
Parameters T, T! and T!L
The off-delay time T, the prewarning time T! and the prewarning period T!L can be provided by the actual value of another already-programmed function:
Analog comparator: Ax - Ay
Analog threshold trigger: Ax
Analog amplifier: Ax
Analog multiplexer: AQ
Analog ramp: AQ
Mathematic instruction: AQ
PI controller: AQ
Up/Down counter: Cnt
For the 0BA7 and later version devices, you can additionally use the actual values of the following already-programmed functions:
On-delay: Ta
Off-delay: Ta
On-/off-delay: Ta
Retentive on-delay: Ta
Wiping relay(pulse output): Ta
Edge triggered wiping relay: Ta
Asynchronous pulse generator: Ta
Stairway light switch: Ta
Multiple function switch: Ta
Stopwatch: AQ
Analog filter: AQ
Average value: AQ
Max/Min: AQ
Threshold trigger: Fre
You select the required function by the block number.
Timing diagram
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The prewarning time is set to 15 s. The T! and T!L parameters thus become obsolete. |
Changing the time base
You can change the prewarning time base and the period.
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Time base T |
Prewarning time |
Prewarning period |
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Seconds * |
750 ms |
50 ms |
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Minutes |
15 s |
1 s |
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Hours |
15 min |
1 min |
Description of the function
Output Q is set to 1 with a 0 to 1 signal transition at input Trg. The 1 to 0 transition at input Trg triggers the current time and output Q remains set.
Output Q is reset to 0 when Ta reaches the time T. Before the off delay time (T - T!) has expired, you can output a prewarning that resets Q for the duration of the off prewarning time T!L.
Ta is retriggered (optional) at the next high/low transition at input Trg and if Ta is expiring.
Scan cycle time
For information on how to determine the scan cycle time of a LOGO!, refer to the appendix of the LOGO! Manual.