Siemens SIMATIC S7-200 System Manual page 153

In order to determine if the transitions between waveform segments are acceptable, you need to
determine the cycle time of the last pulse in a segment. Unless the delta cycle time is 0, you must
calculate the cycle time of the last pulse of a segment, because this value is not specified in the
profile. Use the following formula to calculate the cycle time of the last pulse:
Cycle time of the last pulse for a segment = Init_CT
where: Init_CT = Initial cycle time for this segment
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Delta = Delta cycle time for this segment
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Quantity
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While the simplified example above is useful as an introduction, real applications can require more
complicated waveform profiles. Remember that the delta cycle time can be specified only as an
integer number of microseconds or milliseconds, and the cycle time modification is performed on
each pulse.
The effect of these two items is that calculation of the delta cycle time value for a given segment
could require an iterative approach. Some flexibility in the value of the ending cycle time or the
number of pulses for a given segment might be required.
The duration of a given profile segment can be useful in the process of determining correct profile
table values. Use the following formula to calculate the length of time for completing a given profile
segment:
Duration of segment = Quantity
where: Quantity
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Init_CT = Initial cycle time for this segment
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Delta = Delta cycle time for this segment
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= Quantity of pulses in this segment
* ( Init_CT + ( ( Delta
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= Quantity of pulses in this segment
S7-200 Instruction Set
+ ( Delta * ( Quantity
seg seg
/2 ) * ( Quantity
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Chapter 6
-- 1 ))
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-- 1 ) ) )
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