Please give some suggestons and programming tips for the problem given below

mudaza

Member
Join Date
Apr 2009
Location
Karachi
Posts
16
Hi,My name is Mudassir Azam i am a Trainee Engineer working in a Electronic Engg. Firm , I need to design a project by using your PLC a water filling system.
Suppose a house consisting of two tanks,the underground and the overhead and a pump motor.The Underground tank consist of a Low Level switch(LLS) and the Overhead tank consist of a High Level Switch(HI) and a Low Level Switch(LO).
Conditions of motor when to switch "on" and when to switch "off" (NOTE:the motor is "on" and "off" automatically):
1. When the water in the Underground tank is above LLS or when the Underground tank is full, then the motor remains "on" and as the water is below LLS or when the Underground tankis empty,then the motor remains "off".
2.The water filling status in Overhead tank is when the tank is empty the motor is switch "on" or below LO.And the motor is "off" when water in Overhead tank is full or above HI.
The consumption of water from overhead tank should be shown as an effect on programming.
(NOTE:please program the above logic in FBD,LAD and explain the procedure of the program,the water should also be determined as well )
icon5.gif
 
(NOTE:please program the above logic in FBD,LAD and explain the procedure of the program,the water should also be determined as well )
icon5.gif

Mudaza, I think nobody is going to make you a program here, i know it for sure, but i´m sure that many people are going to help you after you show your efforts to solve the problem.

First off all, tell us what is your platform, if you dig a little bit i´m sure that you´re going to find some examples that can help you with your problem.
 
Thank u Mr.Bill for your kind suggestion,when i was working on my project,(NOTE:the following situation should be done with the Overhead tank),i got a problem with the output of the pump motor that the pump should not be switch "on" on the consumption state of water,that as the water level began to decrease from HI to LO the motor starts ,whereas the motor should not start in consumption state ,when the water decreases below LO(NOTE:approximately emptiness of Overhead tank) then only the motor should start as according to the requirement being provided to you by me.
icon9.gif
 
Your system is very much like a motor with a start pushbuton, a stop pushbutton, and an emergency stop button.

The upper tank low level switch acts like the start pushbutton.
The upper tank high level switch acts like the stop pushbutton.
The lower tank low level switch acts like the emergency stop.

I'm hoping that in your training you heve been shown a simple start/stop circuit and that you can see the similarity between that basic circuit and the system you are trying to control.
 
Thank u Mr.Steve u made the thing easier for me can i get some automation videos as well,to get an industrial overview
 
Last edited:
Mr.Steve i, checked your program but still the consumption state is not working properly the motor should start only when the water level decreases below LO and the motor is starting as water level decrements below HI
 
u r making some mistake in programming otherwise this will not happen..... which contact of LLS are u using & how u r using it, if possible send the screen shot of ur program we will help u...

Parag
 
If you are interested in videos, you can also check out PLCMentor.com. I have been posting videos on various plaforms there since November last year. Ron's videos are good - I added them to our site the day after he made them available. As far as email addresses, I suspect most here will just want to use the forum. Its flexible and it allows others to benefit from the discussion.

Russell

Russell
 
Mr.Steve i, checked your program but still the consumption state is not working properly the motor should start only when the water level decreases below LO and the motor is starting as water level decrements below HI
Hello Mudaza,I'm no expert on PLC's but yet understand the basic concept. In your case I'd say that if you post a screenshot of want you have so far someone will be able to help you out. From the problem that you have described, I suspect that you might have used an incorrect instruction in your program.eg.NC instead of NO
Check your instruction for the LO input. This input should only be true when the water level goes below this limit switch and should go false again as the water level goes above this. You will need to use a seal in contact here to keep your pump running until the water level goes above your HI limit switch.
Hope this helps.......
 
Mudassir,

Your pump ladder rung should look similar to this. This logic assumes that your Low Level Switches are open when low, and closed when not low, and the High Level switch is closed when high and open when not high.

If your switches are different, you must change the logic.

HOUSE WATER TANKS.jpg
 
Last edited:
Thank u but i do have some other logic please check these out as well,i guess that they might be right i am forwarding some other also and then tell me.Ok

Snap1.jpg Snap2.jpg
 
Last edited:
I'm not sure I understand what B2 is doing. Actually I have read and reread this thread and I am still not sure about what you are trying to do. I do know that you will need some delay or some method similar to the seal in Lancie's example to stop chatter in your pump contactor. Keep in mind that when the level passes through the point of one of your switches, the switch doesnt just change over and thats it. There is generally ripples in the liquid that will cause the switch to open and close as it passes through that transition that will need to be accounted for.
 

Similar Topics

Please help me, I have solve many week but still not solve it. I found trouble of factory talk studio when I set tag by browse address of OPC...
Replies
0
Views
79
Hello Everyone, i Have im my Industry a Endress & Hauser Promag400 this has a screen that constantly have that error, it says to wait, somebody...
Replies
2
Views
425
After replacing the 70 with the 525, the PLC can read from the drive and recognizes it as online, but no commands are being listened to. PLC is...
Replies
1
Views
492
To quickly test a plc output which is wired to a relay do I dob a cable between the output and 24vdc+ source I.e something with 24vdc+ live such...
Replies
6
Views
629
Hello all, A little background. Our organization is exploring using the Siemens S7 1500 PLCs in the future. We are an Allen Bradley's house...
Replies
16
Views
1,882
Back
Top Bottom