Help

Hi Guys,
I have just started a PLC course and i am stuck on a question and its not that i am looking for someone else to do my work there are loads of these questions if i could just get started and use this one as a reference that would be great is there any kind souls out there willing to help me cheers thanks here is the question...........
write the Boolean Equation, the truth table, the circuit diagram, and ladder diagram which will solve this scenario.

A water tank is filled by a pump (X). There are two elements in the tank to heat the water if certain conditions are met (Y & Z). The tank is equipped with a temperature sensor (A) and two level switches (B & C). There is also a switch (D) that an operator can use to determine the level of water in the tank.



If switch D is off, the tank will fill to the lower level (B) and the water will be heated by one element (Y). If the operator switches on D, the tank will fill to the higher level (C) and the water will be heated by both elements..... My e-mail is budsmith75@hotmail if you can help you can send it there or even have any tip's for a beginner thanks again

First things first

Hi TRIGGER,

Welcome to our world of PLCs.

This writings for you are my birthday's fun here at fti.is in Iceland.

Try first to list up outputs. Outputs are the result of Boole Equation as you probably know.

Outputs are:

X=Pump
Y=Element1
Z=Element2

Inputs are

A=Temperature Low temp= make High temp = break (NC) normally closed
B=Lower level Normally open (NO)
C=Upper level Normally open (NO)
D=Level selector ON/OFF

The first Boole Equation for the X could be
(D(NOT)AND B(NOT)) OR (D AND C(NOT))= X

That means if selector D is OFF and the level sensor B is also OFF the pump start. OR if D is ON and the level sensor C is also OFF the pump start.

What kind of PLC do you have?

I hope this will start helping you.

Until next time,

SIS.

I agree with SIS - I always start with an I/O point list.

Teh electrical diagram would be a "ladder diagram" electrical schematic of the hardware involved. This site can help get you started: http://www.patchn.com/

Start writing the ladder diagram by breaking the logic into steps, starting with a simple one. The tutorial on this site will help. Add bits and pieces one at a time until you have the logic complete.

thanks guys will give it a go if i am still stuck i will get back to ya cheers

COULD SOMEBODY HELP I DOWNLOADED THE LOGIXPRO 500 SIMULATOR AND I WROTE A PROGRAME FOR THE SILO SIMULUTOR AND DO YOU THINK IT WILL WORK FOR ME IF THERE IS ANY BODY OUT THERE THAT HAS DONE IT BEFORE COULD YOU PLEASE PLEASE PASS THE LADDER LOGIC ONTO ME BEFORE I PULL MY HAIR OUT THANKS ......e-MAIL IS [email protected] or just reply to me here thanks and waiting trigger