Fehlemann Picomax 100 Retrofit

Before assembly there has to be chaos. I removed the unused 24v ac circuit and the 6v ac circuit for the machine light. Also removes the 12 dc circuit for the microscope I don’t have including the power supplies.



also moved the encoder lines and the analog servo control to the place where Mesa boards will be. Did this after I removed the old control completely.



I decided to use a wireless mpg, so I removed everything including the connectors. This way I was able to reuse the hole for the connector for the Ethernet connector.



did I mention it was one of the best ideas to use the parapet channel in the shop. So it was a quick job to route an additional Ethernet connection to the machine.



it was the first step towards reassembly. Next ist to tinker around how to mount the computer 

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the front alloy frame is really beefy so I can use it for mounting the computer. 

At the moment the Z column can go to three (five if you include top and bottom) heights automatically. The positions are set by moving the cams for the position switches. YOu you’ll always move the column manually to any Pictionary within its travel. There is no real feedback from the column on what height it is. I wonder If I could / should change that.
First thing I had in mind was to treat it as an axis and add Glas scale.
But the motor to move the column can only get the signals up, down and Pos 1-5. And has an brake amplifier, so setting up an axis with pid doesn’t seam to be an good idea. And I have to deal with the kinematics of the column and the quill moving the Z axis.

Second thought was using a glas scale and external offsets. This looks for a damn simple solution for me. Only two question come to my mind. Soft limits I read the manual, but didn’t get it. I want soft limits for the quill travel and could calculate theoretical limits for the whole Z axis which would be 0 and -730mm. This way the Quill won’t ram itself on to the table (which it could when moving the column down).
Can this be done? Are external offsets stored on shutdown (I susially store machine coordinates)? Does it male sense? Are there some better solutions out there?

Thanks Patrick

Damn I looked at the external offset samples and I think they are made for something different. They result in an actual movement of the machine. I could invert the signal, so the machine tries to keep the quill in the same height when the column is moved.

At the moment I don‘t know how I can use an encoder feedback from the column to enhance the capabilities of the machine.
But it is not essential to have the feature to get the machine running. So this will be postponed.

the Mesa boards are still stuck in customs, so I took the time to bring my Ideas from cardboard to CAD



in the void right to the computer will com a 3d printer holder for the programmable key pads.
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Found some 150x12mm aluminium in the shop which I can use for the computer and will be bolted to the existing quite beefy aluminium frame.
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in the next days I will prepare the aluminum parts. The cover I sent out for laser cutting out of 3.2 mm aluminum plastic laminate stuff. I the end this might look rather professional compare to my other retrofits (But I am quite sure I find a ways to make it look trashy)

Not much progress over the last time.

but I printed a sheet to mount the USB ports in and the switch for the control power.

the keypads arrived and I printed a carrier to later mount the on the interface​

 

Monday I can pick up my mesa boards, the all the hardware, except the laser cut sheet and the hand wheel has arrived. 

 

With the Mesa boards ready for pickup, I found the motivation to make some progress and made the monitor mount.
This took longer than expected cause the reference switch on the Y-Axis got stuck. But after a some massaging the old machine worked again

The control power supply got a new breaker with an integrated ELCB. Wich is also providing power to the socket on the control panel.

the I Installed the New 24V and 5V power supplies

last step was preparing the din rails and wiring channel for the mesa boards:

Thats all for today.

Cheers Patrick

the mesa boards are here ant Iv'e tested then

ping for first contact:



Second contact with sserial board



third contact linuxcnc



I am happy! everything seems to run, so its time to bring everything to the machine...

time to bring everything to the machine...

found the time this weekend to finish the control power switch:





this was the last step needed to mount the computer. So I installed the mounting bracket 



and then the computer:



 

Later printed out the spreadsheet for relocating the old wires



then it was time to start the wiring by mounting the mesa boards to the din rails



in the end I was able to rewire the first three connectors.



and the 5V power supply is ready, but while doing this realized that the spindle has no encoder, I didn't know how that could slip my attention, at the moment it uses an analog tachometer for feedback to the VFD. So I have to figure out what I will do about it.

Inputs are done, analog Outputs and some of the digital outs. But more to come