what is best?

a big trashcan manufacturer has asked us to make a PLC-program so he can see on a tp a graph on how the lid of this trashcan opens.
because these are expensive trashcans he wants them have the same opening graph at the end of the production.
this to prevent him from customers who saw another trashcan of the same type open faster and that kind of stuff.
we are now at the point of choosing some type of sensor and i like to hear the opinion of you guys

our first option is a ultrasonic sensor to detect the changing distance between the sensor and the lid.

our second option is a lasersensor for detecting how the lid opens

we want the signal of the sensor to go to an analog input module

the PLC we are planning to use for this project is a mitsubishi FX1n-60MT an the TP is gonna be a F940GOT(at least looks like we are gonna use those 2 form this point)

according to this info what do you guys think is the best sensor to detect how the lid opens?

BTW we have no acyual type of sensor in mind for this yet only those sorts of sensors

"so he can see on a tp"

toilet paper?

I think more information is required, particularly speed and distance and type of movement of the trashcan lid. If it is moving too fast or is rotating rather than linear then an analog input may not be fast enough whatever the sensor you use. When I last looked at using a analog PLC input for speed and distance measurement, the fastest update time was 4msec, this limits the fastest speed that you will be able to detect.

the sensor will mesure 50 points and between each point is a time of 100msec.

those points will be send to the TP and will be set in a trend graph.

at the end you see a nice graphic with all 50 points in it. i tested it by moving each 100ms a variable, for example k5, into the tp and that works fine something like this comes out of it(only this looks nicer than reality it has less corners in it):

Looks like you got the screen figured out. what is the independent variable (X) and what is the dependent variable ? how does the trash can lid work ? is it a hinge?

I am not sure I understand the application. Are you wanting to "measure" the lid and determine it matches specifications? Then graph the dimensions onto a hmi/touch screen? Please provide more details.

I will offer this as an option though. Sick optics make machine vision cameras, which sounds like it may fit the application. They also offer measurement sensors: http://www.sickusa.com/live/master/default.asp

You can also access their German, if that would help, from this page: http://www.sick.com/home/en.html Look on left of page.

it is about the speed the lid opens.

if you press on the lid it will open by a spring atached to rear of the lid. when pressed the first part of opening goes fast but if its almost fully opened the opening speed reduces. and the lid opens slower and slower untill its fully opened.

the manufacturer of these trashcans wants all the lids of the same type of trashcan to open the exact same way( a minor difference is allowed).

for this he asked us if we could make an installation that could messure that speed en get a trend of the whole opening, where does he opens fast en where slow, on a TP.
if we can make that, he chooses a lid that opens perfect according to him and then we can make a from the opening of that lid and safe this trend into the PLC so we can call it when the next lid is tested to see if it opens the same.

for messuring the speed of that opening we wore tinking about the 2 sorts of sensors mentioned above. but we have no idea wich one would be the best for this job. and that is what my question is.

teh screen i attached is only an example cause the lid wont open that way. the variables x and y are gonna be in milliseconds.

hope you have an idea of what we are trying to do cause my english isn't that good. that is why i have a crappy description about the job.

1. How big is the lid?

2. Is it a correct assumption that it follows an arc? If so, what's the total travel angle? This will help determine the distance range required by the sensor (ultrasonic, or laser)

3. In your graph, does the x-axis represent time, or velocity, or position?

4. What's the material and color of the trash can lid?

5. Describe the environment in which the tests will be performed.

If you can attach to the pivot point, an angle transducer may give better, more repeatable results than a laser or ultrasonic sensor. You may be able to build a jig that attaches to the pivot point (with magnets maybe?), and requires no calibration or special alignment from one test to the next.

Using an ultrasonic, laser, or other optical means of sensing will require that the sensor is set up exactly the same way for every test, and possibly, frequent calibration. Also, some sensors may not produce a linear output proportional to the distance.

I have some experience with most of these types of sensors. I've always seen variations in repeatability and linearity with every ultrasonic sensor I've used. This is going to be even more true if the angle of the surface you're focused on is changing. Lasers tend to be much better. We use an angle transducer made by Lucas Schaevitz that is extremely repeatable, linear and trouble free.

Just a thought

I would shy away from the ultrasonics because of its sensitivity to temperature. Put a dog on a rotary encoder similar to the Schaevitz as OkiePC mentioned on the lid hinge and now you've got a pulse to collect data with against time.

I agree with the rotary encoder idea but the Fx1n has HSC inputs so use a standard pulse output encoder (I think this is what jstolaruk is saying), get a very light one and fix it to an arm that sits on the lid when it is closed and the lid pushes it up on opening. This could be done on a conveyor to every lid as it passes underneath.