Easy Book
Manual, 05/2009, A5E02486774-01
81
Using the pulse generators of the S7-1200
7
You can configure the outputs of the CPU or signal board (SB) to function as a pulse
generator or pulse-train output (PTO). The pulse-width modulation (PWM) instruction and the
basic motion instruction use these outputs.
Note
Pulse-train outputs cannot be used by other instructions in the user program.
When you configure the outputs of the CPU or SB as pulse generators (for use with the
PWM or basic motion control instructions), the corresponding outputs addresses (Q0.0,
Q0.1, Q4.0, and Q4.1) are removed from the Q memory and cannot be used for other
purposes in your user program. If your user program writes a value to an output used as a
pulse generator, the CPU does not write that value to the physical output.
NOTICE
Do not exceed the maximum pulse frequency.
As described in the S7-1200 System Manual, the maximum pulse frequency of the pulse
output generators is 100 KHz for the digital outputs of the CPU and 20 KHz for the digital
outputs of the signal board.
When configuring the basic motion instructions, be aware that STEP 7 Basic does not alert
you if you configure an axis with a maximum speed or frequency that exceeds this
hardware limitation. This could cause problems with your application, so always ensure that
you do not exceed the maximum pulse frequency of the hardware.
For information about the basic motion instructions, refer to the online help of STEP 7 Basic.