max pulse frequency

Can anyone confirm for me how fast you can pulse the output on this particular PLC??

http://www.aboutplcs.com/click/Hardware/CPU_Modules/c0-00dd2-d.html

I have never programmed a plc before, so if anyone here can tell me how to get one output to pulse it's highest frequency square wave I would very much appreciate it. A screenshot of the ladder program or a saved project file would be great. Thank you.

I want to test the strength of a particular stepper motor at high speeds and weather or not my load will act like a flywheel and if my gear ratios are ok on my particular setup.


This PLC has free software.
http://www.aboutplcs.com/click/About_CLICK/Features_and_Benefits/free_download.html


If any student or veteran has a little time to program a very quick set of random instructions for the best output on this plc, I would very much appreciate it.
A combination of Ramp up, ramp down and sudden stop is perfect. Please keep the ramp up from 0 to max speed no faster than 1.5 seconds.

Example:

start
Slow Ramp up, 5 seconds
max speed, 10 seconds
slow ramp down 5 seconds
stopped, 10 seconds
Fast ramp up 1.5 seconds
max speed 10 seconds
fast ramp down 1.5 seconds
stopped 10 seconds
fast ramp up 1.5 seconds
max speed 10 seconds
sudden stop
end

Please email the file to [email protected]

I'm using this method because i have one of these plcs on hand and other plans for this plc down the line and i want to get a feel for it and learn by seeing it in action.
Thanks again.

Fireball
You need to show some effort. You question is like me asking you to do all of a project for me so I can just send a bill and collect a check.

If you show some effort and say I have done X,Y, & Z but this or tha is wrong. you may get some good replies.

I am not trying to be a hardA-S-S. I just telling you that you will get a all the help you need if you TRY to do the work yourself first.

fireball1331 said:

Can anyone confirm for me how fast you can pulse the output on this particular PLC??

Click to expand...

fireball1331,

I'm presuming That the Aussie version of this PLC is the same as the stateside version. It would appear that they (Koyo) have some plans for a high speed configurable output, but have not reached that level of development at this time.



That said. It might be possible to get a 125 Hz pulse train output from Y1 by using interrupts.

fireball1331 said:

I want to test the strength of a particular stepper motor at high speeds and weather or not my load will act like a flywheel and if my gear ratios are ok on my particular setup.


A combination of Ramp up, ramp down and sudden stop is perfect. Please keep the ramp up from 0 to max speed no faster than 1.5 seconds.

Example:

start
Slow Ramp up, 5 seconds
max speed, 10 seconds
slow ramp down 5 seconds
stopped, 10 seconds
Fast ramp up 1.5 seconds
max speed 10 seconds
fast ramp down 1.5 seconds
stopped 10 seconds
fast ramp up 1.5 seconds
max speed 10 seconds
sudden stop
end

Click to expand...

This where the problem really exists. There are 8 external interrupts available and 4 software available. I do not believe you will be able to make a smooth enough ramp for your needs

fireball1331 said:

I'm using this method because i have one of these plcs on hand and other plans for this plc down the line and i want to get a feel for it and learn by seeing it in action.
Thanks again.

Click to expand...

I believe at this point in time (the PLC has only been out for a year). You will not be able to accomplish your goal.

Oh! by the way. Welcome to the forum!

JeffKiper said:

Fireball
You need to show some effort. You question is like me asking you to do all of a project for me so I can just send a bill and collect a check.

If you show some effort and say I have done X,Y, & Z but this or tha is wrong. you may get some good replies.

I am not trying to be a hardA-S-S. I just telling you that you will get a all the help you need if you TRY to do the work yourself first.

Click to expand...

My intent was not to leech and get someone to to do all the work for me for free. My original question was for the maximum possible frequency for the PLC that I have to know if my approach was feasible.
I have a background of programming MCU's in C and have never touched PLC's. For some reason PLC's were omitted in my education curriculum. For me to develop my own PCB with my choice of MCU and components for this very simple application is way too time consuming for it to be worth it.

The reason for asking for that simple program was not only to test my stepper motor and mechanical side, but to learn the approach of setting up a PLC and the process of programming it. To do it in C programming language would take a minute and a half with 10 lines of code and i would gladly do it for someone because it takes no time or effort for me because it's second nature. I assumed it's also that easy on PLC's. I assumed that for the time it took you to rip on me in your reply, you would have made 20 clicks with your mouse and sent me an example file from which i could extrapolate the initialization process, loop and subroutine structure, program flow and addressable variable management. From which i could get up on my own 2 feet crawl to my first PLC program by relating PLC programing to what i know from C programing. It's how i learn best (fastest).

Imagine if you were a baseball player and u've never seen cricket being played and was asked to bowl in a cricket match and all you knew is that the ball has to be released from the back part of your hand. You wouldn't instantly know what to do even if you did read a few pages of text with only one picture that didn't include the process. (Let alone all the rules about making a run etc.). If u're a baseball player and watched a full round of cricket, you would relate what you know and what you see and learn millions of times faster than by reading a book.

PS forgive my forwardness, i honestly thought i was asking something excessively simple.

PSS Thank you Vaughn for your well structured and informing replies. Can i ask you how you came to the 125 Hz from the info given on the first page of the datasheet? Namely the 5-20uS on and off response times. 1/40uS =25 000. where am i going wrong with my logic?

Hey fireball, we get a ton of students on here with homework requests, so I suspect Jeff thought you were just another lazy student...I hope you aren't too offended...

You did come to the right place for PLC knowledge...

The Click PLC is cheap and the software's free, but it lacks some features. I am mainly familiar with A/B stuff, so I can't recommend anything that you can program for free, but there are other devices out there with free or very inexpensive software that will have a pulse train output.

You might look at the directlogic line specs here:
http://www.automationdirect.com/adc...tLogic_05_(Micro_Brick_PLC)/PLC_Units/D0-05AD

EDIT: looks like the DL05 can do a 10kHz pulse train output, and you can download a crippled version of the programming software for free (limited to 100 "words").

That same company sells the Click too, and they have great reputation for speed of delivery, support, and quality products.

fireball1331 said:

Can i ask you how you came to the 125 Hz from the info given on the first page of the datasheet? Namely the 5-20uS on and off response times. 1/40uS =25 000. where am i going wrong with my logic?

Click to expand...

It looks like Koyo is planning to have a pulse train output for Y1 available in the future, just by looking at the response times. When I look at what they have done with the DL05 and DL06 and the high speed outputs, it seems to be a natural fit. My guess is that a firmware revision as well as a programming software upgrade would be needed.

I based my estimation of what is possible from my experience with scan times. The only way you currently have access to the output is through ladder logic. The manual states the typical scan times as being 1 to 2 ms. This sounds like wishfull thinking to me. If all you had to do was make the pulse train with no ramps, this might happen with a 2 ms scan time. and that should give you a theoretical 250 Hz. But when you place the math to do a ramp into the mix, my gut feel is that the scan time would double. Plus it would also be inconsistent. Because you are trying to get a "feel" for your stepper design constraints the inconsistency would be a deal breaker.

On the other hand. If you already have the "Click" in hand. What is to stop you from some experimenting?

Edit: I see Paul has replied with some excellent advice.

milldrone said:

It looks like Koyo is planning to have a pulse train output for Y1 available in the future, just by looking at the response times. When I look at what they have done with the DL05 and DL06 and the high speed outputs, it seems to be a natural fit. My guess is that a firmware revision as well as a programming software upgrade would be needed.

I based my estimation of what is possible from my experience with scan times. The only way you currently have access to the output is through ladder logic. The manual states the typical scan times as being 1 to 2 ms. This sounds like wishfull thinking to me. If all you had to do was make the pulse train with no ramps, this might happen with a 2 ms scan time. and that should give you a theoretical 250 Hz. But when you place the math to do a ramp into the mix, my gut feel is that the scan time would double. Plus it would also be inconsistent. Because you are trying to get a "feel" for your stepper design constraints the inconsistency would be a deal breaker.

On the other hand. If you already have the "Click" in hand. What is to stop you from some experimenting?

Edit: I see Paul has replied with some excellent advice.

Click to expand...

Yes i'm looking at that now. It's double the price but looks like it would do the job perfectly. I don't know how i missed it, i thought read it's specs and didnt meet my requirements. I can't test the Click because i bought a programming cable off ebay and i'm still waiting for it. I picked up the Click from a sparky who replaced it with a new on for one of his clients because 2 pins were busted and forgot which ones but the rest still work fine. So i'm yet to find out and play with it.
I'm also in the process of purchasing a tri plc (sort of, waiting for email quote). Getting my hands on just one plc is driving me crazy. I can't just click to buy online. If there is the option, then it's 2 to 3 times the price than what is available in the states eventhough our dollar now has almost caught up to the US dollar. They all want either minimum of 3 purchase, or to create accounts with them with an ABN etc before they can quote me a reasonalble price. With some MCU's you can request samples for free (upto 3 of each) as long as you have a valid email and postal address, and they send it to you no questions asked. That's the world i come from.

So for now, it's just a waiting game for a couple of days until i finally settle for the plc to use. I was planning to use the Click to learn on and test the most basic operations of my cutting machine individually. Till then, imma hit the books and read up on PLC's and ladder logic. Thanks again

The Click seemed promising by looking at the specs. I knew it didn't have a built in pulse train command but was decieved by the specs and thought it would be possible to get the pulse running at top speed with my own subroutine for pulsetrain.

wish me luck, i need it. It's 4am now, imma hit the sack, more reading tomorow.