Got time?

simplewireman

Member
Join Date
Jun 2002
Location
Oregon
Posts
15
I making up programs as I go along in my learning process.
Here we go..

I have only one start-stop station to which I want to run two motors with a short delay using one timer.

I was sugggested this:

+---- GRT ---+ T4:0.DN MOTOR2
---| T4:0.ACC |-----|/|--------{ }
| 10 |
+------------+
It's obvious that my code is wrong, motor 2 only comes on breafly.
Maybe the whole thing is wrong.

code1.0.gif
 
On Motor 1, you forgot the TT lesson.

On Motor 2, it will come on from when Timer=20 to when Timer is Done (=30 by what you are showing.) Since your time base is 0.1 (sec), Motor 2 will be on for only 10 x 0.1 sec = 1 sec, which is a pretty short time.
  1. Set the time base to seconds (and maybe increase the Preset to 60),
  2. Change the DN to TT
  3. Don't forget to break the B3:0/0 seal with the DN, or you'll be forced to push the STOP to reset it.

When posting ladder in ASCII like I do (or when quoting some), put the HTML code [LAD<tag>DER] at the beginning, and- very important- [/LAD<tag>DER] at the end. All the spaces will then be preserved. (I find posting code this way easier than creating a picture to attach - you may feel differently)
<hr>
Where did I learn French? When I was 10, my family moved to Belgium, and I even attended public school there for a while. It was strange trying to learn a third language (Flemmish) through the filters of a second language (French), especially since Flemmish is a Germanic language, like English, while French is a Romantic language.

I probably only spoke a child's pidgin French. Never used it when we moved back to the States. Took it again in college, but didn't study it hard enough to become fluent (again?).
 
It is exactly what I was trying to do.
I'm not using RSLogix to do my programming but LogixPro thelearningpit.com from William Simpson. It's a great program for learning LogixPro hasa built-in simulator and it's under $30.US, I can go wrong. But I dont think it has the flexibilty that RSLogix as in inserting branches as you did.

It is exactly what I was trying to do. Here is another question.
How similar would the program be if I was tryng to start only one motor, that has start windings and run windings. That would mean that I would have to put a timer between the start and run. The project mentioned above was one that I had to put together for one of my Electrical Code Update (required by state law to renew electrical license)We given two magnectic starter and timing relay.
So I thought of that project(as a self-learning project)and see what kind of trouble I can get myself in.

I greatly appreciate your imput and assistance. :)
And I'll to see if my LogixPro can do this. Keep you posted.
 
I was able to accomplish what you suggested Alan, thanks.
I'm wondering looking at Logic versus ladder diagram. On a diagram I imagine I would a see set of holding contacts for the coil to run the motor, correct...?
So, I guess what doing here is basically incorporating ladder diagram including coil holding contacts to logic. In your program I don’t a coil but I do see an energized timer. I’m I to assume that the individual that would follow the logic would assume that the coil and holding contacts were there.

code 1.1.gif
 
I don't know that I'd do all that much differently - probably just use the B3:0/0 instead of T4:0.EN on rung two.

This is a somewhat different Sequence-Of-Operations than you've set for yourself in the past. Before, you were interested in having a motor running for a set period of time after pushing START (with another starting after a delay, but both stopping at the same time)

Here, you have one motor controlled by the Start/Stop, and the other one delayed from the first one's start.

This last one is closer to how things usually need to be programmed (but the former is not unknown).

I suppose logically, your next self-challenge would be the dreaded Traffic Light problem (It's only dreaded by students who have not taken the time to learn how to program each element, such as you are; and by us, who have to deal with such students. The problem itself is not that hard.) We'll help you through that one too, if you wish, but I hope you can find something else. You've been doing great so far!
 
Ah yes the dreaded traffic light. That's a bridge that I will come to one of these days, but it's low on the priority list. My main focus are timers and all associated function, after they are the guts of the traffic light...enough said. It's time out (pardon the pun)

I found a site that did have a ladder diagram for a walk/don't walk system. http://www.eos.ncsu.edu/eos/info/ie...guide/node31.html#SECTION00340000000000000000

I'll examine it, translate it, put it in my LogixPro and learn how to make it work, without harming or dammaging anything. I've heard stories that some individuals misprogrammed and ended taking out the side of a wall when a gate should have been open and instead it was closed, I guess this doesn't work there anymore....You think?

Everyone have a nice day and thanks for the support. :)
 
There is no difference in the 2 programs as far as function. It is just personal preference of design. Though I agree with Allen Nelson if you are using an intermediate bit (b3) then I would use this instead of the enable bit. Regards Alan Case
 

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