Values of I/O tags

An object of I/O tag type may acquire values in the system, which are described for individual types in the following tables (only the types, listed below, are described in the tables).


I/O tags of Di type - Logical input

Object value Cause
D_False *FALSE value
D_True *TRUE value
D_Oscillate Oscillating value (TRUE <-> FALSE). The system sets a value as the oscillating one according to defined parameters of filtering - Oscillation limits

*Valid for the normal polarity. In case of the inverse polarity, then opposite values are valid.


I/O tags of Dout type - Logical output

Object value Cause
D_False *FALSE value
D_True *TRUE value
D_Oscillate Oscillating value (TRUE <-> FALSE). The system sets a value as the oscillating one according to defined parameters of filtering - Oscillation limits

*Valid for the normal polarity. In case of the inverse polarity, then opposite values are valid.


I/O tags of Qi type - Quaternary input

Quaternary inputs are used e.g. in electricity industry. Example of use: opening a pulp valve with logical sensors of the end positions closed and open - can contain the following states:

  • the value of the sensor open is True, the value of the sensor closed is False, the value of the quaternary input is open - On
  • the value of the sensor open is False, the value of the sensor closed is True, the value of the quaternary input is closed - Off
  • the values of both sensors are False (the pump valve is between end positions), the value of the quaternary input is transition - Trans
  • the values of both sensors is True (it can be caused by e.g. a communication error or physical sensor damage), the value of the quaternary input is error - Err
Object value Cause
Q_Off OFF value
Q_On ON value
Q_Trans TRANS value (ON-OFF change or vice versa)
Q_Err ERR value (error state)
Q_Oscillate Oscillating value (On <-> Off). The system sets a value as the oscillating one according to defined parameters of filtering - Oscillation limits.

Initial values of I/O tags after starting D2000 system and after restarting process D2000 KOM

If no control object and no default value are defined for an I/O tag, its value will be invalid after starting the D2000 system.
After restarting process D2000 KOM, process internally invalidates the values of all I/O tags. This could be undesirable behaviour (e.g. the values of output I/O tags in server protocols), therefore starting process D2000 KOM with the parameter /KI allows to enable loading the initial values of I/O tags (input as well as output ones) from process D2000 Server after starting process D2000 KOM.

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