PTO Functions: Simple Motion Control

Notes  ♦

When an Output is not being used in a channel, it may be used as a general-purpose output (not high-speed)

Caution  

These functions are based on programming logic, and therefore do not have the safeguards generally provided by electro-mechanical controls. It is the user's responsibility to implement those safeguards required by his system, such as override and/or emergency stop mechanism.

Parameter Name

Purpose

Vision Model

Select the appropriate model

Channel

A Channel comprises the inputs used to carry out the PTO function, and determines their function

Mode

The possible modes are:

• Pulse

• Pulse + Direction

• Clockwise/Counter Clockwise

The tables in the previous section give all possible combinations and output assignments, based on model.

Switch

Switch reverses the tasks of the PTO outputs that are assigned to the channel in modes Pulse + Direction or CW/CCW. This can be helpful to fix cases where the output wiring is reversed.

Unit

PTO functions rely on Units. This is where you determine the number of pulses per Unit.

Note that neither values for Unit nor Pulses per Unit may exceed 1000

Note -  To control your output using straight frequency,  set  1 pulse = 1 unit.

 Calculate Frequency to Units according to the following

Status Messages

0  - No error

1  -  Invalid configuration data

2  -  VisiLogic/OS mismatch; this OS version

3  -  Vision outputs do not support function

4  -  Invalid structure

5  -  Invalid configuration channel

6  -  Unit or Pulse per Unit exceed limits (1-1000)

7  -  Channel already initialized

8  -  Currently in motion ( function cannot be performed during acceleration or deceleration)

Success Bit

Turns ON when the Status MI =0

Parameter Name

Purpose

Channel

Select the relevant channel

Start/ Stop Velocity

These parameters determine the limits of the motion profile for the channel.

Note that the resolution of velocity is according to the units set in the PTO Configuration.

Maximum Velocity

Acceleration Time

(mS)

Deceleration Time

(mS)

Jerk Factor

Controlling for jerk influences the shape of your motion curve.

Legal values are from 1 to 16, where 1=trapezoidal curve and 16 =perfect S.

Status Messages

0  -  OK

1  -  Invalid configuration data

2  -  Currently in motion ( function cannot be performed during acceleration or deceleration)

3  -  Invalid channel

4  -  PTO Configuration block does not exist

5  -  Out of range

6  -  Maximum value is out of range

Success Bit

Turns ON when the Status MI =0

Parameter Name

Purpose

Channel

Select the relevant channel

Movement Type

This sets the type of movement:

• Absolute Position
  This causes movement to the exact position requested, without considering the current position.

• Relative Position
  Here the movement is relative to the current position.

Velocity

Note that the resolution of velocity is according to the units set in the PTO Configuration.

The Move velocity must be greater than the Start/Stop velocity

Target Position

Sets the desired goal

Status Messages

0  -  Idle / OK

1  -  Configuration data is invalid

2  -   Invalid channel

3  -  Channel not initialized, or Vision outputs do not support function

4  -  Absolute Movement cannot be performed

5  -  Currently in motion ( function cannot be performed during acceleration or deceleration)

Success Bit

Turns ON when the Status MI =0

Parameter Name

Purpose

Channel

Select the relevant channel

PTO Stop

• Immediate
  Intended to cause an immediate, emergency stop with no regard for position or any other parameter (requires parameter reset)

• Normal
  Stops motion according to the rate of deceleration set in the PTO Configuration.

Status Messages

0  -  Idle / OK

1  -  Already stopped

2  -  Invalid channel

3  -  Channel isn’t initialized

4  -  unknown command

Success Bit

Turns ON when the Status MI =0

Parameter Name

Purpose

Channel

Select the relevant channel

Current Position

Use these as a reference for Move functions

 Note that the resolution of velocity is according to the units set in the PTO Configuration

Velocity

In Progress

This turns Off after the values have been read.

Status Messages

0  -  Idle / OK

1  -  Currently in motion ( function cannot be performed during acceleration or deceleration)

2  -  Channel is not configured

3  -  Invalid channel

4  -  Read Timeout

Success Bit

Turns ON when the Status MI =0

Parameter Name

Purpose

Channel

Select the relevant channel

Offset: PTO Set Home

The channel uses this value to set the reference point for the next move operation. If, for example, the Absolute target is set to 600, and the Offset to 200, the channel will move to 400.

Status Messages

0  -   OK

1  -  invalid channel

2  -  precondition error

3  -   Channel is currently accelerating or decelerating ( Movement can only be performed when system is Idle of in steady state)

Success Bit

Turns ON when the Status MI =0