Index

PSIM
The TON Timer
Introductory Lab


 

The "TON" Timer

  • From the Main Menu of the PSIM program, select the I/O simulation display.
  • Toggle Function Key [F2] until the minimum I/O Data Table is displayed in the upper box of the display, and the Timer Table is displayed in the lower box of the Data table display.
  • Select the Rung Editor [F5] and enter the following ladder Logic program.

  • Once you have entered your program, select the Program Utility menu and save your program to disk. Now exit the Rung Editor and return to the I/O simulation Display.
  • Note the initial value of timer T1's accumulator, preset and the state of both its done and enable bits.

T1:A = ___________ T1:P = ____________ T1/DN = ____ T1/EN = ____

  • Close switch I:0/00 and observe the incrementing of T1's accumulator and the setting of its Enable and Done bits.
  • Note the final value of timer T1's accumulator, preset and the state of both its done and enable bits.

T1:A = ___________ T1:P = ____________ T1/DN = ____ T1/EN = ____

  • Toggle the state of switch I:0/00 a number of times and observe the operation of the Timer.

 

Cascaded Timers

  • Ensure that switch I:0/00 is open; then Select [F5] the Rung Editor and modify your program so that it matches the following:

  • Once you have completed your program, save it to disk and return to the I/O simulation display. Toggle the state of switch I:0/00 to ON and observe the operation of the timers in your program.
  • Pay particular attention to the way in which the timers are cascaded. (Timer #2 is enabled via the done bit of Timer #1).

 

Self Resetting Timers

  • Ensure that switch I:0/00 is open; then Select (F5) the Rung Editor and modify your program so that it matches the following. (XIO T:2/DN instruction on Rung 1)

  • Once you have modified your program, save it to disk and return to the I/O simulation display.
  • Toggle the state of switch I:0/00 to ON and observe how the timers are now fully cascading in their operation.

 

 

 

 

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