How to use and control a time delay switch TD_SW1.

[trimus]

I just started to use multisim pro ver 7.0 . I need to learn how the time delay switch TD_SW1 is used in a circuit.  I understand that the switch has an associated Ton and Toff but when I place it in a circuit and set the Ton=1 and Toff=2 sec and start the simulation, nothing happens.

What event starts the TD_SW1 switch delay timer?

I need to know how the TD_SW1 switch can be used to do the following:

1) After 5 sec, the switch should change state (if closed change to open).

2) After 5 sec, the switch should toggle to open and stay open for 3 sec and then close again

3) the switch should change state 5 sec after a key is pressed. 

Thanks!   

[nestor-sg]

Hi, well first of all, has your simulation time counter on the bottom right side of the application reach the 1 sec and 2 sec you are expecting? Remember that simulation time differs quite a lot from real-time. Is slower, so it might be happening that you have not yet reached 1 sec of simulation event after 40 or 50 seconds of our time depending on the complexity of the circuit.

Secondly, I would say that for the three points that you specify the TD_SWITCH might no be your best bet. The time delay switch has a fixed absolute time setting. You might need to use a different approach... you could:

• Use a voltage controlled switch along with the piecewise linear source to specify time and voltage levels.
• Use the ladder diagrams and electromechanical components to build timers and time contacts.
• Completely build some timer circuits with some clock circuitry and switching circuitry using RLC and transistor components.