High-Speed Pulse Output - Siemens SIMATIC S7-200 System Manual

CPU and Input/Output Configuration

High-Speed Pulse Output

The S7-200 CPUs support high-speed pulse outputs. Q0.0 and Q0.1 can either
generate high-speed pulse train outputs (PTO) or perform pulse width modulation
(PWM) control.
The pulse train function provides a square wave (50% duty cycle) output for a
specified number of pulses and a specified cycle time. The number of pulses
can be specified from 1 to 4,294,967,295 pulses. The cycle time can be
specified in either microsecond or millisecond increments either from 50 µs to
65,535 µs or from 2 ms to 65,535 ms. Specifying any odd number of
microseconds or milliseconds (such as 75 ms) causes some duty cycle
distortion. The Pulse Train Output (PTO) function can be programmed to
produce one train of pulses or it can be programmed to produce a pulse profile
consisting of multiple trains of pulses. In the pulse profile mode of operation, the
PTO function can be programmed to control a stepper motor through a simple
ramp up, run, and ramp down sequence or more complicated sequences. The
pulse profile can consist of up to 255 segments with a segment corresponding
to the ramp up or run or ramp down operation.
The pulse width modulation function provides a fixed cycle time with a variable
duty cycle output. The cycle time and the pulse width can be specified in either
microsecond or millisecond increments. The cycle time has a range either from
50 µs to 65,535 µs or from 2 ms to 65,535 ms. The pulse width time has a
range either from 0 µs to 65,535 µs or from 0 ms to 65,535 ms. When the pulse
width is equal to the cycle time, the duty cycle is 100 percent and the output is
turned on continuously. When the pulse width is zero, the duty cycle is 0
percent and the output is turned off.
For more information about the high-speed outputs, see see Section 9.4, SIMATIC
High-Speed Counter Instructions in Chapter 9.
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S7-200 Programmable Controller System Manual
A5E00066097-02