ladder logic : How to put a limit block on multiple analog value

Nyains

Member
Join Date
Dec 2017
Location
New Delhi
Posts
6
Hi,

I want to write a logic, I have total 6 analog input of temperature and have 1 drive.

Now i want to start drive when any one of 6 temperature became high and stop motor when that temperature became low.

I know i can write long logic by Using MOV - CMP but i want to write short logic.


Please help me how to put a single limit block that monitor all 6 temperature value.


Thanks
 
What model of PLC are you using ?

It will very probably be faster to simply use "brute force" to duplicate the logic six times. You could be done before your tea gets cold.
 
For any given homework assignment or task at work, you must consider these instructions as the customers specifications.
1. read the specifications several times.
2. write down your understanding of what you read in a step by step fashion.
3. review what you wrote down and see if it makes since, modify if necessary.
4. step through your notes again this time, you are the one following the instructions.
In other words, you are the plc. Write down on paper the events you are doing.
For example, turn on hydraulic motor 1, write down hydraulic motor 1 on.
If a sensor is needed, write that down.
5. continue through the instructions. When you turn off the motor, mark a line thru it.
6. go through your instructions with all the sensors, motor aux. contacts, outputs
Documented. Modify if necessary.
7. repeat step 6 until no changes are made.
8. Try to group your data words into some organized fashion.
The more programs you write, the more organized you become
9. write the plc program using your notes.
10. install the program and leave in program mode if possible so you can to debug your i/o
11. Question for you, when is a machine and plc the most dangerous and why?
When it’s first powered on – when power is first applied to a machine, you don’t know
How things are wired. When you energize the plc outputs, you don’t know how things
are wired. When the plc is put into run mode the first time, it will do what you told it to do,
NOT what you wanted it to do.
12. debug the program.
13. DOCUMENT EVERYTHING!!!
you may remember things today, but in 5 years and hundreds of programs later, you won't
remember, so DOCUMENT EVERYTHING.
14. MAINTENANCE is your best friend or your worst enemy.
if you work with them and find out what they can do, write the program where they can
trouble shoot the program. they will be able to fix the problem and everyone will be happy.
BUT
if you write the program to where you are the only one who understands what is going on,
maintenance can't fix the issue, the machine is down, production is down, management hears about
it, your boss hears about it, then you hear about it - rewrite the program or else.
you get calls all hours of the day and night.

this still holds true, a machine can cost a billion dollars, but it's not worth 10 cents if
maintenance cannot trouble shoot the issue and fix the issue.

everyone has their own style of programming and you must develop your own way as well.

this is the best advice I can give anyone.
of others has more / better suggestions, feel free to post.
james
 

Similar Topics

I have this program: ZIP (.rss inside no documentation) PDF (Italian documentation) Allen Bradley SLC5/03 PLC. Running on a machine, I want to...
Replies
6
Views
1,492
Hello there, I want to switch on a motor based on the output of the following: If (X LEQ 40 psi) OR (X GEQ 60 psi) Then ... How/where could I...
Replies
14
Views
4,387
Hi all I am trying write a program that has analog input from a pressure sensor in a thank that read the pressure sensor for low level and high...
Replies
23
Views
16,508
Hello to all I used to store the different mail you sent talking about various topics; among them "analog input" As I read it again,I would like...
Replies
5
Views
5,355
I need to output in 4 steps 4, 8, 12, 16 Ma to control rotating device. I have a input window and have the plc values in 4 registers, R1,2,3,4...
Replies
3
Views
2,434
Back
Top Bottom