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Control Engineering?

MstrKurt

Jun 13, 2011
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Hey guys, I am wondering whether anyone on these boards is familiar with Control Engineering?

Thanks.
 

rob_croxford

Aug 3, 2010
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I believe many people will be familiar with the use of controllers and the principles surrounding them. Do you have a particular question?
 

MstrKurt

Jun 13, 2011
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I believe many people will be familiar with the use of controllers and the principles surrounding them. Do you have a particular question?

Well I have a Control Engineering paper I need to complete. However, I have no sources of revision methods to check my answers against and would like to be able to have some sort of revision method before my exam at 2:00pm tomorrow.

I can scan my papers with the questions. Is it ok to post images on these boards?.
 

MstrKurt

Jun 13, 2011
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If images are allowed, please take a look at these pages. You can see i've circled some answers as to what I think is correct. If i could get help on the questions in learning how the answers are obtained i'd greatly appreciate it. Thank you

Page 1:

Page 2:

Page 3:

Page 4:

Page 5:

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poor mystic

Apr 8, 2011
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I thought that question 10 should have been a), and Q19 should aso have been a)... I didn't look at the other 2 sheets but I don't think you're in any trouble.
I wonder though - what level of paper is this please?
 

poor mystic

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well i went back and had a look at pages 3 and 4. I can't guarantee all the answers (I haven't used PLC's myself) but I've attached my responses.
 

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MstrKurt

Jun 13, 2011
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well i went back and had a look at pages 3 and 4. I can't guarantee all the answers (I haven't used PLC's myself) but I've attached my responses.

It is Level 2. And thank you very much for all your help. I'll have a look through them and then edit this post with any queries I have.
 

MstrKurt

Jun 13, 2011
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Level 2? What qualification are you working towards?
It's an embedded module of Control Engineering with NVQ Level 2 in Electronic Engineering.

Regarding the questions:
Would 38 not be C? ( 140mV per Degree, if the Pot is turned 90 degrees 140mV x 90) = 12.6?
Would 39 not be B? (I'm unsure of this question though)

Oh and i'm also unsure how to work out 28? Any ideas?.
 
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poor mystic

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Well I'm sure you're right about 38, good on you. But I'm also sure I'm right about 39. Overshoot is what happens when you increase temperature more than was wanted.
 

MstrKurt

Jun 13, 2011
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Well I'm sure you're right about 38, good on you. But I'm also sure I'm right about 39. Overshoot is what happens when you increase temperature more than was wanted.

Just googled the term "Overshoot" and understand it now :) Thank you for bringing my awareness towards what it was actually asking.

Question 10: Wouldn't a Push button switch Make the circuit before breaking it? as you'd have to push the button down to create the contact?.

Question 19: With a UPS wouldn't that eliminate any possiblity of power supply failure?. (Though I can also see the logic of A, which is the answer I thought on my first read through.)
 
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poor mystic

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... and Q28:
You need the switch to operate 2.25 hours per 12 hours. The word 'per' in English is the same as 'divided by' in algebra.
So, you need the switch to be operated 2.25/12 of the time, or 0.1875 of the time.
The switch is operated by the raised part of the cam, and the cam is on a shaft possessing 360* of angle, if it is in this universe.
The word "of" in English is the same as 'multiplied by' in algebra, so 0.1875 of 360* = 0.1875 x 360 = 67.5*.
Clear as mud, now?
 

MstrKurt

Jun 13, 2011
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... and Q28:
You need the switch to operate 2.25 hours per 12 hours. The word 'per' in English is the same as 'divided by' in algebra.
So, you need the switch to be operated 2.25/12 of the time, or 0.1875 of the time.
The switch is operated by the raised part of the cam, and the cam is on a shaft possessing 360* of angle, if it is in this universe.
The word "of" in English is the same as 'multiplied by' in algebra, so 0.1875 of 360* = 0.1875 x 360 = 67.5*.
Clear as mud, now?

Brilliant explanation. Thank you :).
 

poor mystic

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... as for Q10, if the switch is momentarily off, it is normally on. Hence pressing the switch causes the sequence on-off-on. This is not a push-to-make switch.
In Q19 I really think the examiners want to test your knowledge of engineering practise. A UPS is a pretty hefty piece of equipment to run memory backup for a counter module isn't it? We're only talking about 1 chip here. I think a little battery (correctly a cell, most likely) would be quite enough.
 
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MstrKurt

Jun 13, 2011
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... as for Q10, if the switch is momentarily off, it is normally on. Hence pressing the switch causes the sequence on-off-on. This is not a push-to-make switch.
In Q19 I really think the examiners want to test your knowledge of engineering practise. A UPS is a pretty hefty piece of equipment to run memory backup for a counter module isn't it? We'ew only talking about 1 chip here. I think a little battery (correctly a cell, most likely) would be quite enough.

Ahh I see. Those questions make much more sense now. Thank you.
 

poor mystic

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... the microswitch question is Q5. I had to have a look! Hell! Ok then d) is incorrectly labelled in that the switch contacts in well-draughted diagrams are shown in the normal position. But in d) the switch is shown as closed to a contact marked normally open, which is contradictory.
 

MstrKurt

Jun 13, 2011
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... the microswitch question is Q5. I had to have a look! Hell! Ok then d) is incorrectly labelled in that the switch contacts in well-draughted diagrams are shown in the normal position. But in d) the switch is shown as closed to a contact marked normally open, which is contradictory.
I had a feeling the question was messed up somehow. Would that mean that A is the more right answer out of the 4. However aren't microswitches normally open? by their standard position?
 

MstrKurt

Jun 13, 2011
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Ok. Just for clarification, would that mean the correct answer is A?
Sorry for my misunderstanding.
 
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