Detailed Description

The CTUDOperator is a rising edge counter operator, or CTUD counter as referenced by IEC 61131-3 in PLC.

The CTUDOperator is increasing the count value (CV) on rising edge in the count up input (CU) and decreasing the count value on rising edge in the count down input (CD). The count up output (QU) is set to true when the count value has reached the preset value (PV). The Count down output (QD) is set to true when the count value has reached to zero.

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 CTUDOperator(PV=5) up input (CU, cyan), down input (CD, orange), count value (CV, yellow), up reached output (QU, magenta) and down reached output (QD, green).

Actual Processing Code of the CTUDOperator

unsigned int CTUDOperator<T>::Process()
{
  if (!m_CD || !m_PV || !m_R || !m_LD || !m_QU || !m_QD)
    return STATUS_ERROR;

  if ((bool)*m_R)
  {
    *m_CV = 0;
    *m_R = false;
  }
  if ((bool)*m_LD)
  {
    *m_CV = (T)*m_PV;
    *m_LD = false;
  }
  bool CU = (bool)*m_CU;
  if (CU && m_oldCU != CU && ((T)*m_CV < (T)*m_PV))
    *m_CV = (T)*m_CV + 1;
  bool CD = (bool)*m_CD;
  if (CD && m_oldCD != CD && ((T)*m_CV > 0))
    *m_CV = (T)*m_CV - 1;
  *m_QU = ((T)*m_CV >= (T)*m_PV);
  *m_QD = ((T)*m_CV == 0);

  m_oldCU = CU;
  m_oldCD = CD;

  return STATUS_OK;
}