Detailed Description

The TOFOperator is a off delay timer, or TOF timer as referenced by IEC 61131-3 in PLC.

The TOFOperator output (Q) is set to false after the input (In) is set to false, but only after the preset time delay (PT) has been elapsed.

Arguments

When operator is used inside a signal its default input is automatically tied to signal's InternalValue or previous operator's output. Its default output is automatically tied to next operator's input or to signal's Value. See also CDP Operator Usage In CDP Signals.

Example

Below are the example plots for TOFOperator input (In, cyan), output (Q, orange) and corresponding elapsed time (ET, yellow).

Actual Processing Code of the TOFOperator

unsigned int TOFOperator<bool>::Process()
{
  if (!m_PT || !m_ET)
    return STATUS_ERROR;

  if (!(bool)*m_in)
  {
    const bool timer_started = ((double)*m_ET > 0.0);
    if (m_previous_in_value || timer_started)
    {
      if ((double)*m_ET < (double)*m_PT)
      {
        *m_ET = (double)*m_ET + GetOperatorPeriod();
        *m_Q = true;
      }
      else
        *m_Q = false;
    }
    else
      *m_Q = false;
  }
  else
  {
    *m_ET = 0;
    *m_Q = true;
  }
  m_previous_in_value = (bool)*m_in;

  return STATUS_OK;
}