User Manual

PLC concepts made easy
4.5 Pulse outputs
Easy Book
Manual, 03/2014, A5E02486774-AF
67
Rules
● Overlaying of tags is only possible in FB and FC blocks with standard access.
● You can overlay parameters for all block types and all declaration sections.
● An overlaid parameter can be used like any other block parameter.
● You cannot overlay parameters of type VARIANT.
● The size of the overlaying parameter must be less than or equal to the size of the overlaid
parameter.
● The overlaying variable must be declared immediately after the variable that it overlays
and identified with the keyword "AT".
4.5
Pulse outputs
The CPU or signal board (SB) can be configured to provide four pulse generators for
controlling high-speed pulse output functions, either as pulse-width modulation (PWM) or as
pulse-train output (PTO). The basic motion instructions use PTO outputs. You can assign
each pulse generator to either PWM or PTO, but not both at the same time.
Pulse outputs cannot be used by other instructions in the
us
er program. When you configure the outputs of the
CPU or SB as pulse generators, the corresponding
output addresses 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 u
sed as
a pulse generator, the CPU does not write that value to
the physical output.