lookinf for ideas for my senior Project

[jirah]

hello everyone, Im a engineering student at FIU and im working on my senior project this year. I have a very complicated task that have to be acomplish by the end of the year, and im hoping i can find some guidence of where to start looking for what i need. First things first. I need to build a conveyor belt with a few sensors that will carry some light weight trays filled with soil and seeds. i need to built the conveyor and use some plcs to take the input of the sensors and control the speed of the conveyor and sometimes stop the conveyor depending of the situation. this is the problem put in simple terms. it will get more complex at time goes on and the machine is actually built. As of now, i need to build a simple conveyor with the sensors to do what i have explained above. The problem which this, is that i do not know which plc to use and how am i gonna implemented in the conveyor. im finishing up building the conveyor and about to get to the part where i need to get the pcl functioning with the sensors. so, if anyone has any suggestions or point me in the right direction i would gladly appreciate it. i do not have a motor for the conveyor yet, so if you guys have any suggestions i'm willing to listen.

thanks for your time and help on this matter.

 

[Steve Bailey]

What do you already know about PLCs? What PLC models are available in your lab and what I/O modules? What HP motor do you need? What speed is the conveyor supposed to move? What types of sensors are available in your lab at what voltage do they operate at?

 

[jirah]

what do i know about PLC basic logic class and lab knowledge, programming wise = nothing what so ever.

what plc models are available in my lab at school and I/O modules? none that can be use by out team.

HP motor do i need? this are the motors that i have available but i might have some others but i can guide myself with this ones.

the conveyor will not go fast, may be the same speed as the ones used in the supermarket may be less than that. (more or less so you can have an idea. Speed can fluctuate. But for now lets say the same speed as the ones in the supermarket to start somewhere.

take in consideration that the whole project is being funded by us and nothing is provided by the school but potentiometers, oscilloscopes and things like that. sensors, this is the site where most likely i will buy my sensors. Which is a site where previous friends of mine that have graduated before me have bought theirs.

http://www.sparkfun.com/commerce/categories.php?c=23

if you have any other suggestion, im always interrested.


any other question?
by the way, thanks for your time on this.

 

[jirah]

also i have speed controller available to me.

 

[jirah]

so, basicly the questions from me are.

-which plc could i use?
-where can i buy it and how much am i looking around?
-how to implemented.

i was looking around in ebay and found a couple between 100 and 300

LG PLC G7F-DA2I
LG PLC GDL-D22C
CANLOGIC PLC HE200 PLC288
OMRON CPM2a-30CDR-A PLC

 

[mordred]

well if your planning on speed changes you will either have to communicate the speed to your speed controller the make and model of the PLC will depend on the communication protocal it will accept.
the other way to implement speed changes is to use an analog output card. Some brands of micrologix have one or two analog output channels so does some makes of AB Pico units. the latter is the cheaper of the two problem with the second one is the reduced instruction set. automation direct probably has the most cost effective PLC's
Compared to AB it beats the cost factor easily. Omron isn't bad on cost seimens seems similar to the AB costs but I seldom use that processor so cannot say for sure. Your best bet in my opinion on cost effective purchases I would go with Automation direct. The software is low cost, uses standard cables and their hardware costs considerabnly less than major manufactureres

 

[leitmotif]

Having been a student and using what I can scrounge or on hand I appreciate and understand your position.

OK so here is what I understand your project is
1. Move stuff with conveyer
2. Conveyer linear speed around 1 foot per second
3. Motor and VFD on hand
4. Load is a light load ie no more than a pound or two

You say you will need a PLC to control for unknowns that will be identified in future. I believe you should identify them now and decide if they are an immediate need or a need that may or may not come in the future ie "gotta have now" and maybe "later on's"

The reason for this is to enable you to decide what kind of occurrances you want the PLC to control - and more important - what you need for sensors. I would pick the sensors first to determine what I need in PLC and then of course ensure they will match up with each other.

Dan Bentler

 

[mordred]

I agree with Dan this is a critica step in knowing how many I/O points and of what type your going to need. I was incorrect on the Picos they have some with analog inputs not analog outputs