Stepper via High-speed Output (V570 only)

If you are using a V570 with any model Snap-in I/O module, VisiLogic 7.00 or higher and the OS released with that version, you can use specific high-speed outputs to control stepper motors.

Note that any acceleration and deceleration that is needed to arrive at Target safely and accurately must be implemented in your Ladder application.

Configuring the HSO

  1. Click the Output line and select High Speed Outputs (Step Control).

  1. The Select Operand and Address dialog box appears five successive times, allowing you to link operands for Frequency, Duty Cycle, Run, Current Position, and Target Position.

Parameter

Type

Function

Frequency

MI, ML, DW

Note that F=1/T, where T is the duration time of a complete cycle.  Frequency settings differ from npn to pnp output type.

  • npn: You can use a value of 0, or a value from 8-50000Hz ( 50kHz).

  • pnp: You can use a value of 0, or a value from 8-2000HZ.

Other frequency values are not supported.

Duty Cycle

MI, ML, DW

The ratio of the "on" period of a cycle to the total cycle period. This value may be from 0-1000, and is expressed as a percentage.

If, for example, the constant 750 is stored into the Duty Cycle operand, the duty cycle is equal to 75.0% This means that the pulse will hold a positive state during 75.0% of the total cycle.

In the figure below, MI 22 Duty Cycle Value is equal to 250. This results in the duty cycle being 25% of the total cycle time.

If values out of range enter the Duty Cycle and Frequency operands, the output turns OFF and remains OFF until the values re-enter the range.

Run

MB

Changes the operating mode of the output from normal output mode to HSO mode:

0 (SET)=Normal Mode, 1 (RESET): HSO Mode.

Current Position

DW

This is the current location of the stepper.

Target

DW

This is the location you want the stepper to move to.

Acceleration and Deceleration

If your application requires acceleration/deceleration as is shown in the accompanying figure, you can control the speed of movement via the Ladder application. To see how, check the sample application Stepper Control.