Siemens SIMATIC S7-1200

Extended instructions
9.8 Pulse
S7-1200 Programmable controller
488 System Manual, V4.2, 09/2016, A5E02486680-AK
Note
Digital I/O points assigned to PWM and PTO cannot be forced
The digital I/O points used by the pulse
-width modulation (PWM) and pulse-train output
(PTO) devices are assigned during dev
ice configuration. When digital I/O point addresses
are assigned to these devices, the values of the assigned I/O point addresses cannot be
modified by the Watch table force function.
Table 9- 187 Value of the STATUS parameter
STATUS
Description
0
No error
80A1
PWM identifier does not address a valid PWM.
9.8.2
CTRL_PTO (Pulse train output)
The PTO instruction provides a square wave with a 50% duty cycle output at a specified
frequency. You can use the CTRL_PTO instruction to assign the frequency without a
Technology objects (TO) axis data block (DB).
This instruction requires a pulse generator. You must activate the pulse generator and select
a signal type in the hardware configuration. Refer to "Configuring a pulse channel for PWM
or PTO" (Page 494) for further information.
You can access the CTRL_PTO instruction in the Task Cards, Extended instructions.
Table 9- 188 CTRL_PTO (Pulse Train Output) instruction
LAD / FBD
1
SCL
2
Description
"CTRL_PTO_DB"(
REQ:=_bool_in_,
PTO:=_uint_in_,
FREQUENCY:=_udint_in_,
DONE=>_bool_out_,
BUSY=>_bool_out_,
ERROR=>_bool_out_,
STATUS=>_word_out_);
The PTO instruction allows the user to
control the frequency for a square wave
(50% duty cycle) output.
1
When you insert the instruction, STEP 7 displays the "Call Options" dialog for creating the associated DB.
2
In the SCL example, "CTRL_PTO_DB" is the name of the instance DB.