Overview

 

Pulse Train Output (PTO)

Introduction

The PTO function provides up to four pulse train output channels for a specified number of pulses and a specified velocity (frequency). The PTO function is used to control the positioning or speed of up to four independent linear single-axis stepper or servo drives in open loop mode (for example, with Lexium 28).

The PTO function does not have any position feedback information from the process.

The PTO function can be configured on any output channel of the logic controller not already configured for use by another expert function.

Each PTO channel can use up to:

oSix inputs, if optional interface signals for homing (ref/index), event (probe), limits (limP, limN), or drive interface (driveReady) are used,

oThree physical outputs, if optional drive interface signal is used (driveEnable).

Automatic origin offset and backlash compensation are also managed to improve positioning accuracy. Diagnostics are available for status monitoring, providing comprehensive and quick troubleshooting.

Supported Functions

The four PTO channels support the following functions:

oFour output modes, including quadrature

oSingle axis moves (velocity and position)

oRelative and absolute positioning

oAutomatic trapezoidal and S-curve acceleration and deceleration

oHoming (seven modes with offset compensation)

oDynamic acceleration, deceleration, velocity, and position modification

oSwitch from velocity to position mode and vice versa

oMove queuing (buffer of one move)

oPosition capture and move trigger on event (using probe input)

oBacklash compensation (in quadrature mode)

oLimits (hardware and software)

oDiagnostics

PTO Function Blocks

The PTO function is programmed in EcoStruxure Machine Expert using the following function blocks, available in the M241 PTOPWM library:

NOTE: The motion function blocks act on the position of the axis according to the motion state diagram. The administrative function blocks do not influence the motion state.

NOTE: MC_Power_PTO function block is mandatory before a move command can be issued.

PTO Characteristics

The PTO function has the following characteristics: