thinking about plc's

Discussion in 'General Electronics Chat' started by tony8404, Oct 27, 2008.

  1. tony8404

    Thread Starter Active Member

    Jun 11, 2008
    98
    0
    Hello everyone, I cannot take it anymore. I am sick of my current job,(mail clerk/operation services) just got let down by an employer that i have been in talks with for almost a month, about a job that i had two interviews for. I really thought i was gonna get the job they really got my hopes up until this morning.

    So now i am totally unhappy, i really have to get serious about the electronic field. I am almost now at the begging of my 8th month of school for an electronic systems technician diploma from Coyne american institute. i finish next august, i really have not been reading on the weekends nor putting much effort into my studies. Since i am still not sure what part of the electronic field to head towards i was thinking of PLC'S.

    I have not looked into them that much yet but starting today and before i get discouraged i was hoping for someone to help me in the right direction. Maybe by pointing me in the begging stages or websites or tutorials or maybe books???? i would like to find some websites that start off from the begging or books. i know i have a plc class coming in the new few months. thanks guys for any help sorry still alittle bummed out right now alittle lost for words .
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
  3. tony8404

    Thread Starter Active Member

    Jun 11, 2008
    98
    0
    Thank you Bertus i will look into the sites you gave me. anyone else?
     
  4. gerty

    AAC Fanatic!

    Aug 30, 2007
    1,153
    304
    Here's a free download from Allen Bradley for Picosoft programming software, it'll let you write a program and see it work (or not!). One of my students used it to supplement his programming skills, it has a simulator that shows virtual leds for outputs and if you buy a Pico controller and cable for about $100 each you can actually program it with the software.
    Some of the purists call it a 'controller' not a plc, but most of the programming is the same.
    http://www.ab.com/programmablecontrol/plc/pico/picosoft.html

    edit: the download is in the upper right corner.
     
  5. viju

    Senior Member

    Sep 28, 2008
    120
    0
  6. tony8404

    Thread Starter Active Member

    Jun 11, 2008
    98
    0
    wow guys thank you soo much for responding... i really need to find something to go for and i think it may be plc's... does anyone know if you need a degree to get a job working with plcs? i mean i am getting a diploma as a electronic system technician and was thinking i can learn plcs on my own and then use the diploma with what i learn with plcs to get a job with plcs?

    i know there are two different plcs there is low voltage and high voltage correct? which is the better of the two to learn?

    i would go to itt or lincoln tech or devry but i do not have the time for full time school that is why i keep harping on learning plcs on my own. i was told i will have a class on plcs in the future at my school but wondering what everyone else's take is on it thanks
     
  7. gerty

    AAC Fanatic!

    Aug 30, 2007
    1,153
    304
    The PLCs are the same regardless of the voltage, it's the inputs and output that vary. The programming is the same also, within the same type, that is.
    There are several different brands out there, I'm only famalliar with Allen Bradley. Learning on your own is no easy task. The places I've been there seems to be two levels, technician and programmer. The tech needs to know how to trouble shoot and wire it up. Programmer needs to be sure the machine is safe and efficient.

    edit: The tech needs to know enough about the program to be able to see where the problem is, whether its
    a machine fault,electrical problem, or program glitch.
    To clarify above about the PLCs being the same, you buy the plc with the appropriate input/output voltage cards.
    The PLC itself is the common part.
     
    Last edited: Oct 28, 2008
  8. tony8404

    Thread Starter Active Member

    Jun 11, 2008
    98
    0
    ahhh i see.. did not know there was a tech and a programmer. i was wondering if i read on plcs and get familiar with them, i was thinking of taking the 1 plc class they have at my school if i might be able to get an entry level position and then work my way up. i am trying to find the easiest or the best way to begin learning plc's i have
    taken the links that were posted in this post and have been reading on them but nothing there says how to begin or where... any takers?
     
  9. tony8404

    Thread Starter Active Member

    Jun 11, 2008
    98
    0
    also, i noticed alot of online stuff with plc's kinda like training sites that require payment. are these good or stay far away from them?

    also, i have seen kinda like kits as well for plc's how bout those?
     
  10. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
    Hello,

    I think now two different items get mixed up.
    PLC's are programmable logic controllers.
    PIC's are periphial interface controllers.

    Greetings,
    Bertus
     
  11. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    I have used Crouzet PLC's and they are very easy to program, you use function blocks and connect them together with wires on the screen rather using ladder diagrams for programming.

    Have a look at them here:

    http://www.crouzet.com/filiales/ltd/html/en/crouzet-homepage-en.htm

    Also, they have a manual which explains what each function block does.
     
  12. ssherwood

    New Member

    Aug 25, 2008
    9
    0
    PLC's are fun to work with, I do it every day for building automation and HVAC. I have seen many systems, and am good at just a few. If I were starting out in the programming of PLC's, I would first brush up on simple logic devices. The and, or, comparator, flip-flop, delay on make/break relays, PID devices, etc. Understanding these will bring you far in your studies, however, each brand has their own spin on how the devices are programmed to form logic control, and they call stuff different names.

    Once you get your feet wet there, then you'll need to know basic electrical concepts. For example, many low voltage (24vac) modulating(Proportional) motors use a 0-10vdc signal, 135 ohm "wheatstone bridge" signal, or a 4-20mA. Inputs can come in the same form, or will be dry-contact, or 0-5vdc. Sensors can be any, temperature sensors are typically 10K(Balco) or 3K thermistors, and transducers are often 0-5 vdc.

    There's much to learn, hope this helps atleast a little. When I started, I began drawing logic control sequences for boiler plant operations. Always more to learn! Good Luck, let me know if you need any specifics.;)
     
  13. ssherwood

    New Member

    Aug 25, 2008
    9
    0
    Maybe I posted this in the wrong spot at first? Response is to Tony.
    PLC's are fun to work with, I do it every day for building automation and HVAC. I have seen many systems, and am good at just a few. If I were starting out in the programming of PLC's, I would first brush up on simple logic devices. The and, or, comparator, flip-flop, delay on make/break relays, PID devices, etc. Understanding these will bring you far in your studies, however, each brand has their own spin on how the devices are programmed to form logic control, and they call stuff different names.

    Once you get your feet wet there, then you'll need to know basic electrical concepts. For example, many low voltage (24vac) modulating(Proportional) motors use a 0-10vdc signal, 135 ohm "wheatstone bridge" signal, or a 4-20mA. Inputs can come in the same form, or will be dry-contact, or 0-5vdc. Sensors can be any, temperature sensors are typically 10K(Balco) or 3K thermistors, and transducers are often 0-5 vdc.

    There's much to learn, hope this helps atleast a little. When I started, I began drawing logic control sequences for boiler plant operations. Always more to learn! Good Luck, let me know if you need any specifics.;)
    [​IMG]
     
  14. tony8404

    Thread Starter Active Member

    Jun 11, 2008
    98
    0
    ssherwood, sorry for the delay on a response to you but i am glad you chimed in because i was hoping to hear from someone that actually works with plc's. my last teacher did but he does not teach nights anymore, he went to day classes so i cannot pick his brain lol.

    ssherwood, alot of the terms you used in your post put me at a loss but thats cause i have not gotten my feet wet as of yet. i am afraid to dive into plc's without a correct starting point. there are some good sites that others had posted for me on the first page but i am looking for a starting point can you help me out with this? if it helps you out i have not taken my low voltage class as of yet. but is there a place or a part of the plc's i can call the starting point or the beginning? i would hate to pick something to start with and find out later that i should have done it different or the place i started should have been the last thing i should learn lol. also, do you know if there is that much of a demand for plc guys?
     
  15. vetterick

    Active Member

    Aug 11, 2008
    35
    0
    Tony, I work with these things daily (well not really I work 3 days a week), we have them on everything from vacuum casting furnaces larger than a house, to simple sump level alarms.

    Normally we only let the Electrical Engineers program PLCs, but I've been known to write and alter programs as well as an electrician, they are fun at first but like everything else once you figgure it out its just another job.
     
  16. tony8404

    Thread Starter Active Member

    Jun 11, 2008
    98
    0
    lol... i understand totally but where does one start out with plc's? i just wanna take the proper steps thats all. i do not wanna start where i am not supposed to and then dislike plc's cause i do not understand cause i started to far ahead. i just wish there was a start here or read this first type thing, maybe i am not inputing the right words into the search engines out there. lol
     
Loading...