FYI, until further instruction, I am ignoring all drawings except for needhelp3.pdf because I don't know the story behind them.

Still waiting for those limit switches to be added to needhelp3.

Please excuse me if I start probing into things which might seem a distraction from your specific question, but to be completely transparent, If I do this I'm trying to get a feel for the accuracy of needhelp3.pdf.

Getting started, it looks like your raise button does absolutely nothing and the raise relay coil is connected directly to +24V. Is this the case? If so, the raise button should do nothing, and it should be impossible for you to ever lower the saw since the raise and lower relays appear to be electrically interlocked.

What is the line coming out the left side of the selenium rectifier? another 0V line?
What is the line coming out the bottom side of the selenium rectifier? another +24V line? a -24V line?
Where does the +24v to all the buttons come from?

Is the operator supposed to hold the button until it reaches the correct height, then release it? That would make a little more sense to me. The contactor wouldn't need to latch in that case.

For the lower solenoid its a different operation. You wouldn't expect the operator to hold the button while the saw was cutting. That contactor needs to latch but also needs a way to unlatch. There is no direct switch to disengage the contactor for the lower solenoid either.

I disagree with your statement in bold. I do believe that, if there were no button installed to stop a downward stroke, then the only possibility is that in the original configuration, the operator was required to hold the Down button in. As a matter of fact, I would think that it should be a safety requirement to have it this way, in case for any reason (including, but not limited to the operator being pulled into the saw) the operator releases the down button, it stops going down. I would also expect the saw motor on function to not be a latching circuit for the same reason. Look at other saws on the market, especially the large chop saws, have a trigger which must be held in for the operator to run it.

I think that the raise and lower functions were momentary functions and someone had the bright idea to try and make them latching functions. They got half way through and lost track or got confused, and couldn't get it back to the original setup OR make it latching so they effectively "ruined" the saw so they sold it to you.

 

Please find attached a working drawing. I have checked it so that everything works, but simply and without added complication.

The 24V transformer and rectifier are not shown in the drawing, as I suspect that your contactor coils may in fact be 24V AC - you will need to check them, as there is a difference.

I also think the solenoids may be using 24V DC - so you will again need to check that, and you may need to take the supply to the relevant contacts after the rectifier.
I have no idea how large the solenoids are, but I would advise using quenching diodes across the contactor contacts.
If they are very large you can use the main contacts on the contactors, as they are otherwise idle.

Finally the drawing is based on the following assumptions.

1) Saw Motor latches ON once button is pressed until OFF button is pressed
2) Hydraulic Motor latches ON once button is pressed until OFF button is pressed
3) UP & DOWN buttons are manually pressed and do not latch
4) Emergency stop button will cause all contactors to drop out and all motors to shut off.
5) I have shown the main on/off switch on the 24V circuit, but I suspect it may be on the mains supply before the transformer.

 

Cork_ie, I like your drawing. it is much easier to understand. I propose that any further modifications to the drawing by OP or anyone, be made to this drawing and not needhelp3.pdf or other drawings.

I also like how you moved the electrical interlock from the relay contacts to the pushbuttons. Much simpler.

OP, please verify that the raise/lower pushbuttons have NC contacts.

 

Cork_ie,

Nice job on the drawing. I agree with strantor's suggestion.

 

Cork_ie,

Nice job on the drawing. I agree with strantor's suggestion.

MS Paint is surprisingly useful for this kind of work.

I have done a lot of work, over the years, on German equipment and they are the masters of over-complication.

I am a great believer in the KISS principal (Keep it Simple and Straight forward) , that is why the Japanese have been so successful.

 

I think this is the same saw. Very similar.
http://youtu.be/LucKi9bMoJ0

 

I think this is the same saw. Very similar.
http://youtu.be/LucKi9bMoJ0

Now that saw has a lower limit switch, which causes the saw to stop descending and rise to the upper limit.
It also has variable speed control.( velocidad variable)

I have never seen your saw, and can only help, by going on the information you have given me.

If you want the saw to stop cutting and rise to the upper limit once it reaches the lower limit, then that is technically possible.

 

I'm putting together a youtube video right now. Its going to be static pictures but gives a very good idea of what we are dealing with. I appreciate all you are doing.

 

http://youtu.be/Q9yvDwd_o8o

Here is the beast.

 

If I were you I would wire it up like in the drawing I posted earlier.

It is simple and safe and more than adequate for occasional use unless you want it for heavy commercial use.

From what I can see of the 2 YouTube links, the first saw has a variable speed feed to control how fast the blade descends through the timber, yours doesen't.
This is something you need to consider before latching the downward feed as there are different feed rates for softwoods and hardwoods. You would most likely overheat and destroy your blade with an uncontrolled descent.
Even worse, you could cause the blade to jam and endure lots of consequential grief.

 

Mine has that adjustable feed on it just like the other video. I didn't have a picture of that side of the saw. Its a knurled knob on my saw.

I was the lucky winner of a Siemens LOGO! PLC on ebay. I'm considering using it. It has 6 each 24VAC inputs and 4 outputs. I could probably get rid of the contactors for the solenoids and just go straight to the solenoids from the PLC.
I have the LOGO! software and have been playing with that.
But ideally I would like to have it wired up like it came from the factory.

 

I don't know how it was wired up coming from the factory.

How is the variable speed you refer to controlled at the moment, or at least the last time this thing was working?

I need to know exactly what you want to do, so that I can alter the schematic to suit.
Can you please post a step by step sequence of operations.
i.e.
1)Turn on main switch
2) Start Saw
3) Start Hydraulic Pump
4) etc. etc.

This thing looks like it fell overboard off Noah's Ark and I doubt it currently has any fancy electronics on it.

 

Let me work on that list for you.

Noah used this to help make his ark. Its a piece of history although not mentioned in the bible.

 

Its a piece of history although not mentioned in the bible.

More like a case of O'Connell's Law
"The amount of junk accumulated is directly related to the space available to hold it"

 

More like a case of O'Connell's Law
"The amount of junk accumulated is directly related to the space available to hold it"

Must be an irish thing, this O'Connell's Law. We have Murphy's Law here.

 

I'm putting together a youtube video right now. Its going to be static pictures but gives a very good idea of what we are dealing with. I appreciate all you are doing.

Ah, ok, I was picturing something like this.

Do you have reason to believe that the saw came with the automatic "down, stop, up" feature? perhaps that's what the unknown button is for (to stop the sequence)?

If not, I would just go with cork_ie's circuit as its the safest thing you could have.

 

BTW do go by the name "shanghyd" on other forums, or is that the previous owner? I came across that name on one of the machine forums while searching for pehaka then I saw it on your saw.

 

That's one of my other handles. There have been many over the years. Its about time for another change. I think I'll go with James Brown or John Smith or something very common.

 

ok. you were asked questions in post #23, 32, and 36 which you've yet to answer. does that mean that you're satisfied with cork_ie's drawing as is, and we're done here? or does it mean that you're going to go rewire the machine per cork_ie's drawing and get back to us? or some other thing?

Sorry, the thread just seems to be in limbo and I'm not sure if you feel your issue has been resolved or if you're still waiting for something more.

 

Must be an irish thing, this O'Connell's Law. We have Murphy's Law here.

Murphy's Law is "If anything can go wrong it will go wrong"

Another one is Parkinsons Law "Work expands so as to fill the time available for its completion".

The O'Connell's Law is a family Joke . It is my surname and I come from a long line of hoarders!!