Siemens SIMATIC S7-200, Системное руководство

Страница: 285 / 866

Program instructions
7.7 Pulse output
S7-200 SMART
System Manual, V2.3, 07/2017, A5E03822230-AF
285
7.7 Pulse output
7.7.1 Pulse output instruction (PLS)
The Pulse output (PLS) instruction controls the Pulse train output (PTO) and Pulse width
modulation (PWM) functions available on the high-speed outputs (Q0.0, Q0.1, and Q0.3).
When using PWM, you can use an optional wizard to create the PWM instructions.
LAD / FBD STL Description
PLS N
You can use the PLS instruction to create up to three PTO or PWM opera-
tions. PTO allows the user to control the frequency and number of pulses for a
square wave (50% duty cycle) output. PWM allows the user control of a fixed
cycle time output with a variable duty cycle.
Error conditions with ENO = 0 SM bits affected
•
0005H: Simultaneous HSC/PLS
•
000DH: Attempt to redefine pulse
output while it is active
•
000EH: Number of PTO profile seg-
ments was set to 0
•
0017H: Attempt to assign resource for
PTO/PWM that is already assigned to
motion control
•
001BH: Attempt to change time base
on enabled PWM
•
0090H: N is not 0, 1, or 2.
•
0091H: Range error
None
Input / output Data type Operand
N (channel) WORD Constant: 0 (= Q0.0), 1 (= Q0.1), or 2 (= Q0.3)
The CPU has three PTO/PWM generators (PLS0, PLS1, and PLS2) that create either a
high-speed pulse train or a pulse width modulated waveform. PLS0 is assigned to digital
output point Q0.0, PLS1 is assigned to digital output point Q0.1, and PLS2 is assigned to
digital output point Q0.3. A designated special memory (SM) location stores the following
data for each generator: a PTO status byte (8-bit value), a control byte (8-bit value), a cycle
time or frequency (unsigned 16-bit value), a pulse width value (unsigned 16-bit value), and a
pulse count value (unsigned 32-bit value).