Siemens Simatic S7 Series System Manual

Program instructions
7.7 Pulse output
S7-200 SMART
System Manual, 09/2015, A5E03822230-AC
255
Result of executing the PLS instruction
Control
register
(Hex val-
ue)
Enable
Select
mode
PTO
Segment
operation
Time base
Pulse
count
Pulse
width
Cycle time
/ frequen-
cy
16#C1 Yes PTO Single Update
frequency
16#C4
Yes
PTO
Single
Update
16#C5 Yes PTO Single Update Update
frequency
16#E0
Yes
PTO
Multiple
7.7.5
Calculating the profile table values
The multiple-segment pipelining capability of the PTO generators can be useful in many
applications, particularly in stepper motor control.
For example, you can use PTO with a pulse profile to control a stepper motor through a
simple ramp up (acceleration), run (no acceleration), and ramp down (deceleration)
sequence. More complicated sequences can be created by defining a pulse profile that
consists of up to 255 segments, with each segment corresponding to a ramp up, run, or
ramp down operation.
The figure below illustrates sample profile table values required to generate an output
waveform:
● Segment 1: Accelerates a stepper motor
● Segment 2: Operates the motor at a constant speed
● Segment 3: Decelerates the motor
To achieve the desired number of motor revolutions for this example, the PTO generator
requires the following values:
● Starting and final pulse frequencies of 2 kHz
● A maximum pulse frequency of 10 kHz
● 4000 pulses

Siemens Simatic S7 Series Specifications

General

CPU	Varies by model (e.g., S7-300, S7-400, S7-1200, S7-1500)
Communication Interfaces	PROFIBUS, PROFINET, Ethernet, MPI
Programming	TIA Portal, STEP 7
Programming Languages	LAD, FBD, STL, SCL, GRAPH
I/O Modules	Digital, Analog, Specialty modules available
Operating Temperature	0°C to 60°C (standard models)
Mounting	DIN rail mounting
Operating Voltage	24V DC or 120/230V AC (varies by model)
Protection Class	IP20 (standard models)
Memory	Varies depending on the S7 model. Includes work memory (RAM) for program execution, load memory (EEPROM or Flash) for program storage, and system memory for operating system functions. Memory sizes range from kilobytes to megabytes.