Duty Cycle; Period Duration - Siemens ET 200SP Manual

4.6.1.2

Duty cycle

The duty cycle corresponds to the ratio of pulse duration to period duration (also referred to
as mark-to-space ratio).
You set the duty cycle in the control interface (Page 117) using OUTPUT_VALUE in S7
analog format (DINT). The sign specifies the direction of rotation of the motor. A positive
value means forward direction. If you set the value 0, the motor is stopped. If you set the
minimum value, the DQn.B is set during the entire period duration. If you set the maximum
value, the DQn.A is set during the entire period duration. If you set a value above or below
the value range, the minimum or maximum value is used.
A changed duty cycle takes effect with the next rising edge at DQn.A or DQn.B.
Output format
S7 analog output
Before changing the direction of rotation, it is recommended to set the value 0 for sufficiently
long for OUTPUT_VALUE in order to first stop the motor. If the motor requires a ramp up or
a ramp down, you must implement the ramp via a corresponding control of the duty cycle.
4.6.1.3

Period duration

You set the period duration from 100 μs to 85 s with a precision of 1 µs in the hardware
configuration.
In addition, you can change the period duration via the control interface by entering a new
value in SLOT as an integer (UDINT). In so doing, you use the MODE_SLOT control bit to
choose whether you want to apply a change once or cyclically:
MODE_SLOT = 0
MODE_SLOT = 1
You can find additional information under Handling of the SLOT parameters (Page 139).
Technology Module TM Pulse 2x24V (6ES7138‑6DB00‑0BB1)
Manual, 05/2019, A5E35061186-AB
Value range of Pulse duration
OUTPUT_VALUE
‒27648 ... 27648 (OUTPUT_VALUE/27648) × Period duration
One-time change:
As soon as you write the value 1
value from SLOT is applied once as the period duration and kept until the
next change.
A change via SLOT takes effect at DQn.A/DQn.B with the next rising edge.
Cyclic change:
When you write the value 17
value from SLOT in each case is applied cyclically as the period duration.
A change via SLOT takes effect at DQn.A/DQn.B with the next rising edge.
Configuring/address space
4.6 PWM with DC motor motor
in the corresponding output byte, the
D
in the corresponding output byte, the current
D
111