plc logix pro

i just started using logixpro and i'm a beginner at plc
and would like some advice on exercise #4 on door simulator.
Thanks

What is your question? What problem do you have?

The first thing to do in any automation project is to define your system.

1) What are the items you're controlling?
2) What are the conditions for them to start?
3) What are the conditions for them to stop?
4) How does the operator interact with the system?
5) How do you detect problems or faults?
6) What should the system do in the event of a fault?
7) How do you reset/clear faults?
8) etc. etc. etc.

I've been doing this kind of stuff for 20 years - and I always go through this kind of process BEFORE I ever start looking at the PLC hardware or code. Doesn't matter if it's a garage door or if it's a multi-million dollar processing facility.

Make a flow chart -- show each step and the condition to transfer from step to step.

Give it a try first, then come back with specific questions. We will help, but we won't do it for you.

thank you i will try this very helpful.
Ozee

Mastergnr7,

Going through Ozee's process with your problem:

1) What are the items you're controlling?
A roll-up door motor

2) What are the conditions for them to start?
Pushbuttons for Open and Close

3) What are the conditions for them to stop?
Pushbutton for Stop, limit switches, one for 100% open, 1 for 100% closed position, and for Exercise 4 only: If door is closing, pressing Open will Stop it. Also, if door is opening, pressing Close will Stop it.

4) How does the operator interact with the system?
Pushbutton station for operator control, plus 3 indicator lights (Open, Shut, and Ajar)

5) How do you detect problems or faults?
Visual observation of the door. (1)It does not move when Open or Close button is pressed, or (2) It does not stop when Stop is pressed, or (3) It does not stop when limit switch is tripped.

6) What should the system do in the event of a fault?
Stop movement of the door.

7) How do you reset/clear faults?
There is no method to clear faults in this exercise, except that built in by the program author (Click on "Simulation, then "Reset Simulation")
8) etc. etc. etc.
Now define the main problem:

If the door is currently opening, pressing the Close Switch SHOULD immediately halt movement. Door movement SHOULD remain halted when the switch is released. If the door is currently closing, pressing the Open Switch SHOULD immediately halt movement. Door movement SHOULD remain halted when the switch is released.

And the solution is spelled out right in the Student Exercise:

The utilization of Binary or Integer Table bits to Flag specific conditions within your program would be appropriate.

Search for the Door Simulator Problem. It has been solved here before. Here is one place where Exercise 4 was discussed and programmed:

http://www.plctalk.net/qanda/showthread.php?t=30256&highlight=door+simulator+exercise

Thank you very much for all your inputs..
Really appreciate it..