newbie to PLC programming

[Daniel45]

I have been using PLC's very many years, I understand what they can do, but new to programming PLC's. I am working on programming an OMRON ZEN PLC for a very simple operation press start button run output 0 for 15 seconds then output 1 for 30 seconds and alternating until the stop button is pressed I have attached my attempt but I have something wrong, I would appreciate help in getting it right. I think once I see it correct I will have a better grasp of how to do this. Thanks

 

[arkyny]

For one thing, I see no timers. Is there more to it than this?

 

[Daniel45]

I thought T0 and T1 were timers they allowed me to select a time for each

 

[jrwb4gbm]

Here is a suggestion. There are other ways to do this. The "coil" for T0 and T1 should be switched on with contacts from Q2 on a separate rung.

 

[gtsuport]

Those are the contact portion of the timer.
You still need to program the timer instruction.

Do you have the programming manual for the ZEN?
It can be downloaded from www.omron247.com

Hope this will help.

 

[Daniel45]

I follow what you are suggesting but not how to execute it (to jrwb4gbm)

 

[gtsuport]

Did you look at the programming manual.
There are examples in the manual.

 

[Daniel45]

I have been reading both the ZEN software support manual and the ZEN operation manual there is so much basic relay logic junk in the ZEN manual I jumped to the software manual and I haven't found what I am after there, I guess I will have to just wade through all the "noise" usually I can just pick this kind of thing up and figure it out with out having to read every word in the manual

 

[balash]

something like in pic.
do not know how to reset timer.
timer coil = timer input

timers - on delay

EDIT:
in the last rung input = T1

 

[gtsuport]

In the ZEN Operation manual(Z211-E1-02), take a look at
Section 3-6 Using Timers and Holding Timers.

 

[Lancie1]

Old Daniel is probably tearing out hair by now. Here is a big picture hint.
Remember that relays, timers, and counters have two parts: the operating "coil", and the contacts.

 

[Daniel45]

in Lancie1 example I1 has to be NC not NO for the latch to work, but I can't get Q2 to actuate in the simulator?????

 

[gtsuport]

Make sure the simulator is in RUN mode.
If memory serves, it starts up in STOP mode.

 

[Daniel45]

that was it, works now, thanks everyone for the help!

 

[Lancie1]

In Lancie1's example, I1 has to be NC not NO for the latch to work,...

Yes, study on this some more. I1 should be open to look at a closed STOP pushbutton. About 99% of physical STOP pushbuttons have a Normally Closed contact. Why?

Because the physical STOP pushbutton should correctly be NC, what type of PLC instruction do you need to use to LOOK at or EXAMINE that physical stop button and determine if it is ON (N.C. or not pushed)? HINT: It is always the OPPOSITE of the state of the physical STOP button contact. Once you get this clear in your mind, you will avoid one of the most common beginner mistakes in your PLC programs.

I am sure that in your work with electrical controls you have found that STOP control pushbuttons are always N.C. What you really should have done is change the state of your I1 switch contact (not the PLC program instruction "contact") in the ZEN simulator from N.O. to N.C. Then it would have worked as I programmed it for an actual STOP pushbutton.