Values of I/O tags
An object of the I/O tag type may acquire values, which are described in the following tables for individual types (only the types, listed below, are described in the tables).
- Ai - Analog input
- Ao - Analog output
- Ci - Cardinal input
- Co - Cardinal output
- Di - Logical input
- Dout - Logical output
- TxtI - Text input
- TxtO - Text output
- TiA - Absolute time - input
- ToA - Absolute time - output
- TiR - Time interval - input
- ToR - Time interval - output
- Qi - Quaternary input
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 oscillating according to defined parameters of filtering - Oscillation limits |
*Valid for the normal polarity. In the 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 oscillating according to defined parameters of filtering - Oscillation limits |
*Valid for the normal polarity. In the 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 power engineering. Example of use: opening a valve with logical sensors of the end positions closed and open - can be in 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 a transition - Trans
- the values of both sensors are 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 (transition from ON to OFF or vice versa is in progress) |
| Q_Err | ERR value (error state) |
| Q_Oscillate | Oscillating value (On <-> Off). The system sets a value as oscillating according to defined parameters of filtering - Oscillation limits. |
Initial values of I/O tags after starting the D2000 system and after restarting the D2000 KOM process
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 the D2000 KOM process is (re)started, it internally invalidates the values of all I/O tags. This could be undesirable behavior (e.g. the values of output I/O tags in server protocols), therefore starting to process D2000 KOM with the parameter /KI allows enabling reading the initial values of I/O tags (input as well as output ones) from the D2000 Server process after starting the D2000 KOM process.
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