Calculate Revolutions from VFD RPM Feedback

[atc222]

I SMH and wonder.

Lol. You mean diameter changes as cable is fed? You can’t get there from here.

 

[JRW]

This post is similar to 95% of them.(vague)
No one has any idea what the op really has and what he is really trying to do

So I’m assuming...
With his existing hardware...
He wants a estimated length using the speed the drive is running

 

[sparky66]

Either get the encoder feedback inherent in the drive to work, or use an encoder card in the PLC. Any other way is completely half-@ssed.

 

[BITS N BYTES]

Either get the encoder feedback inherent in the drive to work, or use an encoder card in the PLC. Any other way is completely half-@ssed.

Telling it like it IS! Couldn't agree more.

 

[Peter Nachtwey]

This post is similar to 95% of them.(vague)
No one has any idea what the op really has and what he is really trying to do

If my guys were to come to me with a problem like this, I would ask them how can I make such decision when you haven't provided me with the facts.

However, I would never ask them to do what I know is stupid.


When I do tech support for a motion control application the first things I want to know is
How much mass needs to move how far in what time with what accuracy? None of that was provided nor was it asked.


JRW, the plot doesn't show any acceleration or deceleration ramps.


This thread gets a big thumbs down.

 

[JRW]

True
I guess that’s what I get for helping hodge lodge something

But next time I see you trying to put your RMC on a center winder I will reply with SMH too.

 

[VAN]

If my guys were to come to me with a problem like this, I would ask them how can I make such decision when you haven't provided me with the facts.

However, I would never ask them to do what I know is stupid.


When I do tech support for a motion control application the first things I want to know is
How much mass needs to move how far in what time with what accuracy? None of that was provided nor was it asked.


JRW, the plot doesn't show any acceleration or deceleration ramps.


This thread gets a big thumbs down.

I just assume this is a "we have no money and you need to figure it out now" operation. Your we do it right or I'm doing nothing is one approach. But the do nothing isn't going to make your boss happy or get you any favor-ability.

Right now the boss is saying get this thing to move, I'm just saying you have potential ways of doing that. Motion control isn't the only solution. Hell it could be like the lumber industry and just put a big piece of steal in the way to stop the object from moving. That could be enough of a solution for the boss.

 

[Peter Nachtwey]

I object to the mickey mouse suggestions!

@JRW, you should have recommended that the OP get a Siemens winch controller. You do know that Siemens makes winch controllers don't you? I bet it will cost a lot more but it would work whereas suggesting one experiment with a S7-1500 and no good feedback is not right.


There are lots of winch controllers.

True
I guess that’s what I get for helping hodge lodge something

But next time I see you trying to put your RMC on a center winder I will reply with SMH too.

But RMCs work!

One RMC was used to lift 400+ ton sections of the bay bridge across San Francisco bay. There were 3 hydraulic winches that had to be synchronized when lifting and final positioning.

Experimenting was not a good idea.
Neither was ignoring acceleration and deceleration ramps.
This was years ago. I am pretty sure they used multi-turn absolute encoders with an SSI interface. There were either latches or brakes in case hydraulic power was lost. The hydraulic pumps were driven by a motor.

The tricky part was lifting the sections off the barge because once the section was off the barge they didn't want the next wave to lift the barge and hit the bridge section so the motion had to be quick at first.

 

[kalabdel]

rzuhair


Let me know if you want this project for your lab testing- its V16 and uses the Laxis blocks

I'm interested, may have a copy of that?

Thanks

 

[I_Automation]

I just assume this is a "we have no money and you need to figure it out now" operation. Your we do it right or I'm doing nothing is one approach. But the do nothing isn't going to make your boss happy or get you any favor-ability.

Right now the boss is saying get this thing to move, I'm just saying you have potential ways of doing that. Motion control isn't the only solution. Hell it could be like the lumber industry and just put a big piece of steal in the way to stop the object from moving. That could be enough of a solution for the boss.

My answer to similar situations - Sorry boss. It won't work like that. Gonna cost a couple thousand to get this to work.



And then, when it does work reliably, you did good.

 

[Peter Nachtwey]

I just assume this is a "we have no money and you need to figure it out now" operation. Your we do it right or I'm doing nothing is one approach. But the do nothing isn't going to make your boss happy or get you any favor-ability.

When it comes to motion you should have the do-right approach to avoid bad events. Also, doing it right often pays off in quality and speed.

Right now the boss is saying get this thing to move, I'm just saying you have potential ways of doing that. Motion control isn't the only solution.

This is a motion control application. The question is how to upgrade from manual to computer control.

Hell it could be like the lumber industry and just put a big piece of steal in the way to stop the object from moving.

Your example is even ending logs or boards. That works in a saw mill but not for winches.

That could be enough of a solution for the boss.

Does the boss have pointy hair?
What if something goes wrong? A winch that is lifting any amount of weight is potentionally dangerous.



VAN, sawmills tend to do the right thing. They rely a lot on their vendors like USNR and the BID group and a few other system integrators. These guys will not do anything stupid and when they have doubts they call us. The competition is fierce and the liability is too high.


I have spent a lot of time in sawmills. I worked for USNR from 1980 to 1985. I have spent about as much time in sawmills supporting the saw mill OEMs.

 

[VAN]

My answer to similar situations - Sorry boss.

When it comes to motion you should have the do-right approach to avoid bad events. Also, doing it right often pays off in quality and speed.

I don't even have words. Yeah, it'd be great to have the right systems in place.

But I've been in places that yeah we should do it right and a $150k price tag later...

Sometimes sites/people just don't have the money to do it "right" but getting more product out the door beats doing nothing.

 

[GaryS]

When you ay winch are you talking about a crane hoist or a cheap winch that you see on tow truck?

if it's a crane hoist then you should be able to count the drum rotations that may be close enough for what you need.