counters and Timers of Allen Bradley Program

[ronpittc]

Hi how are you guys... i was studying the functions of a counter and timer and in the process, i encounter some commands that im not really sure what they mean for Timer:

1. Timer Enable Bit
2.Timing Bit
3. Timing done bit

Im confuse about this, i know how the timer works, but how come they have this in the programming of PLCs like sometimes they put T4:2/2EN
or T4:2/4DN, i mean what is the difference between the 3 of them... same as the Counter command there is a Counter Up bit, Counter Down Bit and Counter Done Bit... thank you for the help

[Tom Jenkins]

If you read the Allen Bradley programming manual, and look at the example prgrams in the back, you can see illustrations of how these functions are used. I also suspect you haven't read the tutorial on this site.

Helpful as usual, I pity the poor guy you work for. Mind you
with your attitude you probably wouldn't be working for him for
long. Or are you self employed and think your an expert having
done several half *** intergration jobs hahahah!

[Screamin]

Geeeez, obviously somebody got up on the wrong side of the bed this morning

[bernie_carlton]

The questioner, ronpittc, has been pointed to several very helpful manuals and tutorial web sites, including this one. It is my observation, and I think that of Tom Jenkins also, that ronpittc has not sought to use these resources. Though the members of this site can give very insightful answers to particular questions, ronpittc is asking, through the various posts, for the basics of PLC programming to be explained one post at a time. This is very frustrating.

[Kim Gold]

ronpittc:

As Tom points out there is a good explanation of Timer and Counter operation in the Allen Bradley programming manual. Here is a link to the PLC-5 Instruction Set Reference Manual. You can check out the operation of both in chapter 2.

PLC-5 Instruction Set Reference Manual

Kim

[Eric Nelson]

The 'Timing Done' bit (.DN) should be self-explanatory. The other are just there as convenient instructions. Assuming you know that the .DN bit turn on when the timer expires, it might help if you picture the others this way...

|    RUNG CONDITIONS         +-------+

|---] [----]/[----] [----+---| TIMER |

|                        |   +-------+

|                        |

|                        +---( .EN BIT )

|   .EN    .DN

|---] [----]/[---------------( .TT BIT )

.
beerchug

-Eric

Oh, and don't mind the trolls... If we don't feed them, they slowly die off.

Karl told us that a good dose of sunshine turns them to stone, so let's give it a try...

[rogerhollingsworth]

Just so some of us get the feeling that you have done a little reading and research on your own, define what PLC you are using and explain the basics of what you are trying to accomplish.
What part of the book explanation on timers and counters don't you understand? I seriously doubt I could improve on the books explanation and examples but if you have a specific question I will give it my best. Where did you get the address T4:2/2EN, T4:2/4DN?
Is it ONLY timers and counters that you have trouble with or is there a multitude of things?

EN = Enabled(authorized, allowed)
TT = Timer Timing (continuance, in the process of timing)
DN = Done (completed, finished, executed, over)
If the input conditions go true, the timer starts incrementing in
(selected)intervals. When the accumulated(ACC) value is greater than or equal to the preset(PRE)value, the timer stops and sets the timer done (DN)bit.

Stick to one post, don't bounce around.

Roger

[Tom Jenkins]

Well, PLCGuy ole feller, my response to Ron was polite and on topic, which is more then yer remarks appear to be. I felt the info was useful, jist not likely to substitue my work fer his. I jist don't see it likely that a series of on line qustions kin substitute fer an entire text or course, which is the way it looks like Ron is a headin.

As fer my perfessional qualificashuns, I don't reckon I much care whether you know them or not. If I kin help a few people hyar, great. If they don't like my answers, they kin jist ignore them and no harm done.

Well put Tom.

[BobB]

I notice the "rubbisher" did not have the guts to join the forum. Still a guest. plcguy, (do you know what they are?) if you are going to rubbish people, at least have the guts to join and make yourself known.

[rogerhollingsworth]

Probably has joined under another name.

Roger

Hey Ronpittc,

I am not a member but may be able to offer a simple solution to your timer question. I don't use PLC stuff often but:

| I:0 Start Sw1 +-------+ |
|---] [---|---------------------| TON |---<EN>-------------|
| 0 | +-------+ |
| | T4:0, BASE 0.01, Pre 1000, ACC 0 |
| O:0 | |
|---] [---| |
| 0 |
| T4:0 O:0 |
|---] [--------------------------------------< >-------------|
| TT 0 |
| |
| I:0 +-------+ |
|---] [---|---------------------| TON |---<EN>-------------|
| 1 | +-------+ |
| | T4:1, BASE 0.01, Pre 1000, ACC 0 |
| T4:0 | |
|---] [---| |
| DN |
| |
| T4:1 O:0 |
|---] [--------------------------------------< >-------------|
| TT 1 |
| |
| |
|--------------------------------------------<END >----------|
| |
| |
Rung 0: Mash Start Sw1. Timer T4:0 starts and activates the TT control in Rung 1. When the timer expires the 10 seconds T4:0/DN in run 2 closes. This activates Timer T4:1 which closes T4:1/TT in rung 3.

Below is the text for the ladder incase my babbling is unclear.

SOR BST XIC I:0.0/0 NXB XIC O:0.0/0 BND TON T4:0 0.01 100 0 EOR SOR XIC T4:0/TT OTE O:0.0/0 EOR SOR BST XIC T4:0/DN NXB XIC O:0.0/1 BND TON T4:1 0.01 100 0 EOR SOR XIC T4:1/TT OTE O:0.0/1 EOR SOR BST XIC T4:1/DN NXB XIC O:0.0/2 BND TON T10:0 0.01 100 0 EOR SOR XIC T10:0/TT OTE O:0.0/2 EOR SOR END EOR

It's really simple, you just have to play with it a little.

Counters are just as easy, they count up/down when an evert occurs until the set point is reached (kinda / sorta).

I just found this site and find it very interesting. I may join in the near future.

Surfing the web in South Carolina,

Rick

[Eric Nelson]

Rick, you spent a time making you ladder, so don't let it go to waste!...

If you type [ladder] before, and [/ladder] after, your code will look as you intended...

|   I:0 Start Sw1               +-------+                    |

|---] [---|---------------------|  TON  |---<EN>-------------|

|    0    |                     +-------+                    |

|         |             T4:0, BASE 0.01, Pre 1000, ACC 0     |

|   O:0   |                                                  |

|---] [---|                                                  |

|    0                                                       |

|  T4:0                                      O:0             |

|---] [--------------------------------------< >-------------|

|   TT                                        0              |

|                                                            |

|   I:0                         +-------+                    |

|---] [---|---------------------|  TON  |---<EN>-------------|

|    1    |                     +-------+                    |

|         |             T4:1, BASE 0.01, Pre 1000, ACC 0     |

|  T4:0   |                                                  |

|---] [---|                                                  |

|   DN                                                       |

|                                                            |

|  T4:1                                      O:0             |

|---] [--------------------------------------< >-------------|

|   TT                                        1              |

|                                                            |

|                                                            |

|--------------------------------------------<END >----------|

|                                                            |

|                                                            |

beerchug

-Eric

Thanks Eric,

Like I said, Don't do this too often.

Rick