Pete Smith
Guest
P
Hi guys,
Great website, very very helpful.
I'm a 3rd year instrument apprentice, and as part of my apprenticeship, each year, I have to produce and deliver a presentation regarding a chosen subject of my choice. I have chosen PLC's, have written a report, and generated a presentation.
All is good so far.
At the end of the presentation, the managment then torture you and fire questions at you (lol).
I should be ok, but I was wondering if you guys could help me with a few of the questions I'm expecting to be asked.
One of which is analouge to Digital conversion and vice versa. I know if you have an analouge value, it is divided by the number of bits designated (ie 2^14)..with some bits ued for polarity etc) to get the resolution for the output. But what about when you get to the output? digital to analouge conversion? What device is used? Triac outputs?
Another, which I really find hard to answer is, Why use PLCS? I have looked at cost issues, but whats a few relays from RS? Pence? Was thinking reliability, troubleshooting, physical space, ability to reprogram easily (although at my work they are normally programmed, and then left for years until a slight modification or improvement is required..) any other ideas?
Any other questions you can think I may be asked (we are talking quite basic, as the PLC expert isn't attending the presentation..!!).
Thanks for your time,
Pete
Great website, very very helpful.
I'm a 3rd year instrument apprentice, and as part of my apprenticeship, each year, I have to produce and deliver a presentation regarding a chosen subject of my choice. I have chosen PLC's, have written a report, and generated a presentation.
All is good so far.
At the end of the presentation, the managment then torture you and fire questions at you (lol).
I should be ok, but I was wondering if you guys could help me with a few of the questions I'm expecting to be asked.
One of which is analouge to Digital conversion and vice versa. I know if you have an analouge value, it is divided by the number of bits designated (ie 2^14)..with some bits ued for polarity etc) to get the resolution for the output. But what about when you get to the output? digital to analouge conversion? What device is used? Triac outputs?
Another, which I really find hard to answer is, Why use PLCS? I have looked at cost issues, but whats a few relays from RS? Pence? Was thinking reliability, troubleshooting, physical space, ability to reprogram easily (although at my work they are normally programmed, and then left for years until a slight modification or improvement is required..) any other ideas?
Any other questions you can think I may be asked (we are talking quite basic, as the PLC expert isn't attending the presentation..!!).
Thanks for your time,
Pete