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Author Topic: completely new to plcs  (Read 26073 times)
crdfx
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« on: August 12, 2008, 08:28:25 pm »

i have never had any dealing with plcs before and the boss wants me to learn how to write programs so please bear with me and  thanks any help you may be able to give,i have just started with directsoft 5.3 and have no idea what or how to do anything just a beginner and real want to learn again thanks for any pointers
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Greg
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« Reply #1 on: August 13, 2008, 01:31:07 pm »

Hi crdfx, welcome to PLC Land!  Grin

Probably the best thing to do is to get to know your PLC. I would just advise downloading the manual for the PLC you plan on using, and then just start reading from Chapter 1 onward. The basics are dealt with first, and more specific information is given as you go. I know this might not sound like much help, but, trust me, if you are new to PLCs then you need to know what they do before you can really understand what DirectSOFT is allowing you to do.

Hope this helps!
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milldrone
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« Reply #2 on: August 14, 2008, 07:01:59 am »

crdfx,

Let me second the welcome to PLC land!!!

If you are the kind of person that learns from doing and seeing what others have done. Try this approach. Go to
http://forum.automationdirect.com/
And  read the postings of others, see how they solve problems. As you get to know how PLCs work try to solve some of the problems that are posted and compare the results that are posted against what you have done.

Another site that also has a wealth of information is plcs.net.

P.S. Pay special attention to anything Bernie Carlton Posts.
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crdfx
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« Reply #3 on: August 15, 2008, 08:53:20 pm »

thanks guys for the warm welcome i guess its are about reading lol
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milldrone
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« Reply #4 on: August 16, 2008, 06:43:55 am »

crdfx,

As an example. In this post http://www.plctalk.net/qanda/showthread.php?t=41168 at PLCs.net. The original poster wanted a "cleaner", "simpler" way to solve his problem. So I set out to find a way to do it. Fortunately direct soft had a very simple way to do it. I did not post it because he needed a Allen Bradly solution. Actually I found two solutions, but bundled them into one project and saved it for further use.

I made a new project up and tested it out on a plc that I keep at my desk. This plc is my spare parts plc. I do not keep my spare parts "on the shelf" but I put them at my desk so I can test new ways of doing things.

Have fun     
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Vernon Leeper
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« Reply #5 on: August 16, 2008, 08:04:36 pm »

Hello crdfx,
I too am some what new to Direcct Logic's PLC's, cut my teeth on some Allen Bradley stuff years ago. I like the Direct Logic stuff a lot better, thier service is free and more helpful more so than the other guys. Go to the AutomationDirect site and check the training link to Doug Bell's classes, I think if you attend the basic class it would help you understand how to use whatever you chose to do. It was worth the time and money to me to attend, he explains in more detail on what to do and how to do it. Plus the hands on approach is top notch, you won't be disappointed.
This site is a huge, huge, help in anything you are trying to acomplish aswell, there is more tallent , knowledge here than anywhere I have looked.
Good luck on your endervers,
Vern.
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crdfx
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« Reply #6 on: August 19, 2008, 09:00:28 pm »

this is my first job to do with my plc this is a dust collector system main blower is running 30 mins after main blower motor is turned off it  the plc is to start six shaker motors one at a time and run each shaker motor for two mins after all six shaker motors have ran it must start six asco valves one at a time and run them for one minute each so where and how would i program something like this,where do i start? i have no idea how this should look any help thanks Grin
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milldrone
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« Reply #7 on: August 20, 2008, 06:31:13 am »

this is a dust collector system main blower is running 30 mins after main blower motor is turned off   the plc is to start six shaker motors one at a time and run each shaker motor for two mins after all six shaker motors have ran it must start six asco valves one at a time and run them for one minute each

The description of the process is the first step! I think you need more detail (Push buttons, fire system? limit switches, details on outputs). In your description there are questions that need to be answered.
1. Is the main blower to be controlled by the PLC?
2. Your description seems to indicate that this is only done after the main blower shuts down is this true? What needs to happen if there is a power failure during a main blower "run cycle"?
3. Does anything need to happen when the "main blower" starts up?
4. You mention starting shaker motors, but no mention of run duration. You also imply that they need to run individually. What needs to happen if there is a motor overload and a shaker motor is unable to run?   
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crdfx
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« Reply #8 on: August 20, 2008, 08:08:38 am »

the plc is just going to turn on a motor starter contactor for the shakermotors and just going to turn on six asco valves
main blower is not connected to plc
yes everything happens 2hours after main blower is shut down
nothing happens at blower startup
the six shaker motors need to run five minutes one at a time 30 seconds between each motor startup and with overload just move to next motor
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milldrone
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« Reply #9 on: August 21, 2008, 06:52:15 am »


the six shaker motors need to run five minutes one at a time 30 seconds between each motor startup and with overload just move to next motor

crdfx,

There appears to be some inconsistencies between your posts
start six shaker motors one at a time and run each shaker motor for two mins after all six shaker motors have ran it must start six asco valves one at a time and run them for one minute each



This how I'm interpreting your posts correct me if I'm wrong

Project definition:

1. "Main blower" shuts down (PLC needs a way to sense this condition). What do you want to happen if someone starts the main blower for say 1 minute and then turns it off?
2. Start shaker #1, run for 5 minutes.
3. Wait thirty seconds, start shaker #2 run for 5 minutes. 
4. Wait thirty seconds, start shaker #3 run for 5 minutes.
5. Wait thirty seconds, start shaker #4 run for 5 minutes.
6. Wait thirty seconds, start shaker #5 run for 5 minutes.
7. Wait thirty seconds, start shaker #6 run for 5 minutes.

What needs to happen if This cycle is interrupted by something, like the "main blower" starting again?

8. Wait Thirty seconds?Huh? Start asco valve #1 run for 1 minute.
9. Run asco valve #2 for 1 minute.   
10. Run asco valve #3 for 1 minute.
11. Run asco valve #4 for 1 minute.
12. Run asco valve #5 for 1 minute.
13. Run asco valve #6 for 1 minute.

What needs to happen if This cycle is interrupted by something, like the "main blower" starting again?

What do you want to happen if there is no air pressure?

Do you need any indicator lights or push buttons?
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crdfx
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« Reply #10 on: August 22, 2008, 05:53:37 pm »

ok let me try again(sorry about this but like i said never done this plc stuff before)so please excuse me but this is what i need to do this dust collector has a main blower and six shaker motors and six asco valves the main blower motor starter has a set of aux contacts on it that close when blower is running and when the main blower is shut down i need the plc to wait 2 hours and then start 1 of six shaker motors run that motor for 2 minutes then start shaker motor 2 and run it for 2 minutes and so on till all 6 motors have shock and then wait 5 minutes and start asco valve 1 and run it for 1 minute and then wait for 1 minute and start asco valve 2 run it for 1 minute and so on
we have been running shaker motors and asco valves by hand after shutdown but now the boss man wants this plc thing put in to do the job hope this helps and sorry and thanks for your understanding
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milldrone
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« Reply #11 on: August 23, 2008, 09:02:19 am »

crdfx,

OK. So now in your original post you indicated you wanted to learn about PLC's

have just started with directsoft 5.3 and have no idea what or how to do anything just a beginner and real want to learn again thanks for any pointers

I'm taking your description and writing it into steps.

1. Aux contact on Main blower "breaks" (this will be the starting point for your cycle, because you need to wait for 2 hours)

2. Wait two hours.

3. Start the sequence for the shaker motors (two of your posts indicate no time between shaker motor run times and one post indicates 30 second delay) (also one post has the motors running 5 minutes and two posts have them running 2 minutes each)

4. Start the sequence for the air valves (both of your posts that mention air valve times indicate 1 minute blow times, but one post indicates a 1 minute delay between blow times)

5. End of sequence.


BTW Presuming I have the details correct, your program will have these same steps. This is why the details and planning are important.

Questions:

1. Do you have a PLC for this project already?

2. You mentioned that you have DS5.3, do you have it installed in a computer that can be connected with the PLC when it is installed?

3. Do you have any communications gear to connect with the PLC?

4. Are you also doing the wiring and cabinet work?

5. This sounds like a bag house for a woodworking/cabinet shop. What needs to happen if the blower runs for a small amount of time (and hasn't collected any dust). Do you still want to cycle? Or do you want a minimum main blower run time to also be necessary to trigger the cycle?

6. What do you want to happen if the blower turns off and 1 hour and 59 minutes later someone turns the blower on again?

7. Do you need an indicator to inform you that a cycle "will happen sometime in the next two hours"?

8. Do you need a button to cancel the cycle for just one time, after the blower shuts down?

9. You have not indicated you need any help in interfacing with the existing equipment, is this true?

10. Presuming I have the order in the steps correct in the list at the top of this post. Do you just want the code? Or do you want some help so you can do it yourself?   



« Last Edit: August 25, 2008, 09:09:23 am by milldrone » Logged

Vaughn
crdfx
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Posts: 9


« Reply #12 on: August 26, 2008, 08:03:56 am »

answers to above questions
1yes
2yes
3yes
4yes
5no
6 nothing
7no
8no
9yes
10 just code and thanks again
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milldrone
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« Reply #13 on: August 26, 2008, 11:13:57 am »

PLC 06

// Rung 1
// Address 0
#BEGIN COMMENT
"When the main blower stops it will set C0"
#END
STRND X15
SET C0

// Rung 2
// Address 2
#BEGIN COMMENT
"C0 will be reset when C2 is on,  The reset is also performed during a powerup condition. "
"This is because the step will be frozen  in the drum where it was. If you want the step to "
"continue then C0 will need to be re addressed to a retentive range and the SP0 will need "
"to be removed. "
""
"C2 is the last item in the second drum"
#END
STR C2
STR X15
AND C1000
ORSTR
OR SP0
RST C0

// Rung 3
// Address 8
#BEGIN COMMENT
"When C0 is on the drum is enabled"
""
"When C0 is first turned on, it jogs the step to step #2"
""
"Step #2 is 7200 seconds "
""
"The drum is reset when C2 is on. C2 is the last item in the second drum. The reset is also "
"performed during a powerup condition. This is because the step will be frozen where it "
"was. If you want the step to continue then C0 will need to be re addressed to a retentive "
"range and the SP0 will need to be removed. "
#END
STR C0
STRPD C0
STR C2
STR X15
AND C1000
ORSTR
OR SP0
EDRUM CT20 K1 K100 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 C1 Y5 Y4 Y3 Y2 Y1 Y0 K1 K7200 K120 K120 K120 K120 K120 K120 K1 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 K0 K0 K8000 K4000 K2000 K1000 K800 K400 K200 K0 K0 K0 K0 K0 K0 K0

// Rung 4
// Address 83
#BEGIN COMMENT
"When C0 and C1 are on this drum is enabled"
""
"When C1 is first turned on the step is jogged to step #2 (this is so the output is not turned "
"on all the time) This must be one of those feature /bug thingys.  "
#END
STR C0
AND C1
STRPD C1
STR C2
STR X15
AND C1000
ORSTR
OR SP0
EDRUM CT30 K1 K100 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 C2 Y13 Y12 Y11 Y10 Y7 Y6 K1 K60 K60 K60 K60 K60 K60 K60 K60 K60 K60 K60 K1 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 DEF0 K0 K8000 K0 K4000 K0 K2000 K0 K1000 K0 K800 K0 K400 K200 K0 K0 K0

// Rung 5
// Address 159
END

// Rung 6
// Address 160
NOP


#BEGIN ELEMENT_DOC
"X15","","","main blower aux"
"Y0","shaker#1","",""
"Y1","shaker#2","",""
"Y2","shaker#3","",""
"Y3","shaker#4","",""
"Y4","shaker#5","",""
"Y5","shaker#6","",""
"Y6","ascovalve#1","",""
"Y7","ascovalve#2","",""
"Y10","ascovalve#3","",""
"Y11","ascovalve#4","",""
"Y12","ascovalve#5","",""
"Y13","ascovalve#6","",""
"C0","","","cycle"
"C1","start 2nd drum","",""
"C2","reset, cyc done","",""
"C1000","","","if you want the cycle to shut down whenever the main blower turns on remove this bit but leave the main blower aux        "

#END
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Vaughn
crdfx
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« Reply #14 on: August 26, 2008, 12:09:26 pm »

thanks so how would this look in ladder?
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