Timer variables in TONA and TOFA instructions are structure variables. The following table lists the internal structures.
Timer Variable
|
Timer Variable |
Variables Settings |
Description |
|---|---|---|
|
VariableName.TI |
Bit Variable |
Turns ON when the timer begins. |
|
VariableName.Q |
Bit Variable |
Turns ON upon completion of the timer. |
|
VariableName.R |
Bit Variable |
Resets the current value on the timer. Clear (0). |
|
VariableName.PT |
Integer Variable |
The value set on the timer |
|
VariableName.ET |
Integer Variable |
The current value on the timer |
Double-click the timer instruction to display the following dialog box. Enter the preset time in this dialog box.
Enter the setup value and units.
For time-based settings, double-click the timer instruction to display the setup dialog box.
|
Time base |
Description |
PT value/ET value |
|---|---|---|
|
msec |
Specify the time in units of 1 millisecond. |
The PT value is specified and displayed in millisecond units. The ET value is displayed in millisecond units. Setting range = 0 to 214748364 x 1 millisecond |
|
10msec |
Specify the time in units of 10 milliseconds. |
The PT value is set and displayed in units of 10 milliseconds. The ET value is displayed in units of 10 milliseconds. Setting range = 0 to 21474836 x 10 milliseconds |
|
0.1sec |
Specify the time in units of 0.1 s. |
The PT value is specified and displayed in units of 0.1 s. The ET value is displayed in units of 0.1 s. Setting range = 0 to 2147483 x 100 milliseconds |
|
sec |
Specify the time in units of 1 s. |
The PT value is specified and displayed in units of 1 s. The ET value is displayed in units of 1 s. Setting range = 0 to 214748 x 1s |
Program Example
TONA
When the variable of the normally open instruction is turned ON, the elapsed time .ET will increase by the specified time-based units because the TONA instruction is triggered.
The timer measurement bit .TI turns ON.
The timer output bit .Q turns OFF.
When the elapsed time .ET increases to equal the preset time .PT, the elapsed time .ET keeps the current value.
The timer measurement bit .TI turns OFF.
The timer output bit .Q turns ON and allows power to pass.
When the TONA instruction turns OFF, the elapsed time .ET keeps the current value.
The timer measurement bit .TI turns OFF.
The timer output bit .Q turns OFF.
The TONA instruction acts like an accumulator and increases its value. Set the R coil ON to reset the current value.
TOFA
When the timer turns OFF, because the TOFA instruction is triggered, the elapsed time .ET increases in the specified time-based units.
The timer measurement bit .TI turns ON.
The timer output bit .Q turns OFF.
When the elapsed time .ET increases to equal the preset time .PT, the elapsed time .ET keeps the current value.
The timer measurement bit .TI turns OFF.
The timer output bit .Q turns ON and allows power to pass.
When the TONA instruction turns OFF, the elapsed time .ET keeps the current value.
The timer measurement bit .TI turns OFF.
The timer output bit .Q turns OFF.