Direct Logic Question

Hello Folks,
I am new to this forum and i have been learning a great deal from all the good people tying to help NOOBs like me.

I am currently working with DL06 and i wanted to know if someone can help me out. I want to be able to write a ladder logic where i can increase the pressure from a air actuated pump in a steady manner.I dont know if this makes sense or not? If it does i would appreciate if anybody can help me out
regards
Khab0501

If by

in a steady manner

Click to expand...

you meant a constant change per unit of time then do the following.

You will use a timer which can span the needed time frame. A TMRF cna do 100 seconds (0 - 9999 hundreths of seconds). A TMR can do 1000 seconds (0 - 9999 tenths of seconds). If you need a longer time frame then a counter pulsed by a timer may be best.

Start the timer (or timer/counter combination) at the beginning of your ramp time. Calculate the amount of the ramp (ending value - starting value).

On each pass calculate ((current t/ct value * amount of ramp) / (t/ct preset)) + starting value. This resulting number is your reference. It should ramp as smoothly as possible from 'starting value' through 'ending value' over the preset time of the timer.

Actually this methodolgy would work with almost any PLC.

Thank you very much sir. I appreciate your help. Every step i am learning some new ideas.I might have some more questions later hope you dont mind if i post them later.
Sincerely and Regards
Khab0501

khab0501 said:

I want to be able to write a ladder logic where i can increase the pressure from a air actuated pump in a steady manner.

Click to expand...

khab0501,

Here is a thread from the AD forums, with a little more detail. Guess who bcarlton is!

http://forum.automationdirect.com/showthread.php?t=5944&highlight=ramp+analog

I am very thankful to the members here.The more i learn the more i am interested in PLC and automation. I am a manufacturing engineer student in the final year. The project i am working is for the design project. Since PLC programming is not covered extensively in our course so the project assigned to me is pretty much " learning PLC and Ladder Logic from Scratch" I tried multiple sources about PLC in google and finally stumbled across this FORUM and lot of informative and interesting stuff.I have attached a flow chart that i have put together that i am currently working to write a LADDER LOGIC. If people have better ideas i will be very happy to learn and use it in my project.
Sincerely and Regards
Khab0501

That's a weird final year project. Shouldn't it be something to demostrated what you learned for the past few years rather than learning a new tool? How are you ever going to test this logic out even when you are done with it without real world equipment?

Having said that, you need a lot more prep work before you touch the PLC side of things. A flow chart is not a bad start but it's way too busy to use. Some else probably covered this before, but usually..

- figure out the equipment, Input/output, sensors needed.
- Draw a P&ID from the above.
- Figure out logic related to the controls loops.

etc...

Post your P&ID diagram here and we can get you some pointers.

This indeed a weird Project and have been working this stuff for couple of months. We have all the equipments figured out. We are using
1.PLC (D06) from Automation Direct
2.DirectSoft Software
3.Electronic Pressure Controller From Tescom (1-5 VDC)
4.DPT (#2) (Mensor 6010)
5.Relays
6.Air Actuated Pump.
7.Three 3 way valve and one 2 way valve From Sun Hydraulics
8.The max Pressure is 1000 PSI and the Minimum Pressure is 8PSI
10. All the system has been hooked up and The pressure Transducers has been hooked up.

Its been quite a overwhelming Project for me and my 2 other team members. But saying this "we gotta do what we gotta do". But its been a challenging job and we are more exicited learning PLC programming every step we figure out how it works.
We have done bits of here and there from the Flow chart into LADDER LOGIC

And of course as you asked before if we are implementing this project? yes we are making a full scale working model and running some tests

Sincerely and Regards
Khab0501

P.S. I have attached the plumbing diagram if anybody wants to look at it

That's pretty cool that you actually get to play with the real stuff. Shouldn't your instructor be more help?

Anyway, you are still missing some essential part before moving to programming; you need to figure out your control loops, it's best to do this in a P&ID and a I/O list in detail.