Help Help Help Final Year Project

[Student B]

Hi All,



I hope all is well and that someone can help me with this problem; I am a final year Manufacturing Engineer student whose project has just been flipped on its head at the last moment.



So now my project specification has complete changed at the last minute and I have to now use a PLC to control my test rig automactically.



I am building a test rig which is measuring there variables;



Temperature,

Humidity and

Moisture Level



The rig is module and is stacked four high, so that each module is repeating.



The outputs for each module are;

• 1 x set of PC Fans joined in parallel (Voltage 12DC)
• 2 x Solenoid Valves (?)

Input Sensors

• Temperature (40 – 90)
• Humidity and (30 – 90)
• Moisture Level (?)

The Rig has two pump devices which are run from the mains (240V), and also need be controlling, so may need a contactor not 100% sure. These are both outputs.



In total there will be 12 Inputs and 14 Outputs which need controlling.

I have never used a PLC before and only have basic knowledge in C programming.



So what I really am asking is what would someone who has experience in this sector use to control all the above mentioned. I do not have a huge budget either, so please keep cost in mind with suggestions.



I will need to edit the three variables after each experiment for each module.

So Module 1 will have temp set at 70c

Module 2 at 72c

Module 3 at 74c

Module 4 at 68c

And the other variables will be kept the same.

Then in the next set of experiments I will need to reprogram with new values etc.


The PLC will then look at the sensor check the value and then if not at set level turn actutor until value reached. It would be good if the PLC could record the three varaibles through out the expermients




Any help on this matter would be greatly appreciated; I have a tiny time frame, to order the required powers, learn about PLC and programme it. Also any suggestions on the sensors for comparability and prices would be great.



Thanks in advance for any help.



Student B

 

[L D[AR2P#0.0]]

What exactly is your budget and time frame ?
£1000 + 10 weeks ?

 

[Lancie1]

Student B,

A PLC will do the job as you described. For a PLC, there are two basic methods you can use: (1)On/Off control, simple, cheap, but not as precise, or (2)Analog PID control, complex,more expensive, but will zero in to setpoint. You have to decide which method before picking a suitable PLC.

 

[powernxs]

Try looking at Honeywell products to do the PID control I've had great success with their equipment and controls. As far as plc you could possibly use a A-B micrologix 1000 digital to control the solenoids with the micro's relayed outputs and use the same to control the motor starter or contactors. best bet on the plc is using 24vdc inputs and 120vac relayed outputs. Hope this helped

 

[jedft]

Might I suggest a Twido PLC? The hardware is cheap (way cheaper than most AB stuff.. don't know about the ML 1000) and the software is FREE and fairly easy to learn as far as these things go.

Google Twido

 

[milldrone]

We need details from original poster

The original poster needs to read this thread first, http://www.plctalk.net/qanda/showthread.php?t=28755. Then give us the details of the project

Hi All,
I hope all is well and that someone can help me with this problem; I am a final year Manufacturing Engineer student whose project has just been flipped on its head at the last moment.
So now my project specification has complete changed at the last minute and I have to now use a PLC to control my test rig automactically.
I am building a test rig which is measuring there variables;

Temperature,

Humidity and

Moisture Level

The rig is module and is stacked four high, so that each module is repeating.

The outputs for each module are;

• 1 x set of PC Fans joined in parallel (Voltage 12DC)
• 2 x Solenoid Valves (?)

Input Sensors

• Temperature (40 – 90)
  
  
• Humidity and (30 – 90)
  
  
• Moisture Level (?)
  
  

The Rig has two pump devices which are run from the mains (240V), and also need be controlling, so may need a contactor not 100% sure. These are both outputs.

In total there will be 12 Inputs and 14 Outputs which need controlling.

I have never used a PLC before and only have basic knowledge in C programming.

So what I really am asking is what would someone who has experience in this sector use to control all the above mentioned. I do not have a huge budget either, so please keep cost in mind with suggestions.

I will need to edit the three variables after each experiment for each module.

So Module 1 will have temp set at 70c

Module 2 at 72c

Module 3 at 74c

Module 4 at 68c

And the other variables will be kept the same.

Then in the next set of experiments I will need to reprogram with new values etc.

The PLC will then look at the sensor check the value and then if not at set level turn actutor until value reached. It would be good if the PLC could record the three varaibles through out the expermients

Any help on this matter would be greatly appreciated; I have a tiny time frame, to order the required powers, learn about PLC and programme it. Also any suggestions on the sensors for comparability and prices would be great.

Thanks in advance for any help.

Student B

The use of PC fans implies in my mind, one kind of enviorment. The mention of moisture level implies another.

What do the solenoids control? I can guess but I might be wrong.

12 analog inputs ? Thats one large scale final project!

Is this project four of Ron Beaufort's hot rod modules with cooling added in series?

How is the temperature being controlled? I can guess but I might be wrong.


All of these questions (and many more) would be answered with a proper definition of the project

 

[jedft]

Milldrone, in the spirit of the thread you referenced (http://www.plctalk.net/qanda/showthread.php?t=28755)... a full quote of the OP's OP is unnecessary in a response.

 

[CaseyK]

I think this is a good application for an Entertron PLC! "LINK"

You can get analog and digital, and the outputs are pretty robust.

It won't break the bank.

And the programming software is FREE!

You could be programming away while you wait for it to arrive!

 

[leitmotif]

I think you need to step back and define your project. What are you trying to do / prove or disprove / thesis or antithesis.

One of the reasons I say this is you say humidity and moisture level. Humidity (I assume you mean relative humidity) is a measure of moisture level.

So what you need to do is provide us a statement (two sentances) telling us what you want to accomplish or measure.

Dan Bentler