Difference between revisions of "Pulse burst positioning"

Latest revision as of 19:53, 28 August 2015

Illustration of input step pulse & direction signals, motor position and move done output as function of time.

Pulse burst positioning is a setpoint method based on pulse and direction signals. In pulse burst mode, controller need only to generate a burst of pulses with direction signal to begin a motion relative to current position. Motion will comply with pre-configured acceleration and velocity limits of the drive.

Pulse burst positioning properties[edit | edit source]

• Simplicity - easy to understand and implement point-to-point motion
• No real-time pulse train controller needed - smooth motion profile is generated inside the drive
• Exact - setpoint signal path is fully digital
• Change setpoint on the fly - not necessary to wait for motion to finish before sending new pulses

How to use[edit | edit source]

Pulse burst is the minimalistic yet high performing position setpoint method available. Suitable signal may be generated by various means:

• PLC with at least two digital outputs
• A simple timer & counter circuit
• Microcontroller GPIO pin
• Or any programmable device with controllable digital outputs

Practical example[edit | edit source]

Drive parameterization[edit | edit source]

In Argon the following configuration enables burst pulse mode:

• Set Control modeCM as Position control
• Set Setpoint inputCRI as Pulse train & direction
• Set Acceleration limitCAL and Velocity limitCVL to your desired acceleration and velocity values
• Wire J5 connector according to this diagram

Doing incremental move[edit | edit source]

The C-style code below generates the signaling.

void IncrementalMove( int distance )
{
  int i;
 
  /* set direction output pin */
  if(distance<0)
    SetDirectionOutputPin(0);
  else 
    SetDirectionOutputPin(1);
 
  /* generate step pulses to start motion. quantity of pulses = distance */
  for( i=0; i< abs(distance); i++ )
  {
    Delay_ms(0.001); /* wait 1 microseconds or more */
    SetPulseOutputPin(1);
    Delay_ms(0.001); /* wait 1 microseconds or more */
    SetPulseOutputPin(0);
  }
}

• SetPulseOutputPin sets the digital state of HSIN1 pin on Argon
• SetDirectionOutputPin sets the digital state of HSIN2 pin on Argon

Monitoring when motion is complete[edit | edit source]

Returns true when motion has successfully finished. False if timeout expired or drive faulted.

bool WaitForMoveDone( double timeout )
{
  double waited=0;
 
  while(waited<timeout)
  {
    if( GetMotionCompletePinState() == true ) 
      return true; /* motion is now complete, return true*/
 
    if( GetFaultPinState() == true ) 
      return false; /* drive is in fault state, return false*/
 
    /*motion is not complete, wait some time and poll again*/
    Delay_ms(10); /* 0.01 seconds */
    waited=waited+0.01;
  }
 
  /*return false because timeouted */
  return false;
}

• GetMotionCompletePinState reads the GPO1 pin state from Argon
• GetFaultPinState reads the GPO3 pin state from Argon

Usage example[edit | edit source]

IncrementalMove(500);
WaitForMoveDone();
IncrementalMove(1000);
WaitForMoveDone();
IncrementalMove(-1500);
WaitForMoveDone();