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Fehlmann Picomax CNC 51 ("HVBV" relay, documentations)

Jenkins

Plastic
Joined
May 15, 2022
Copying... Done!
Before copying i did several investigations of what this box should do and how, in order to test it well before inserting to the machine.
Briefly saying, this is 3 phases reversing contactor for the 380V AC motor, in this machine it is driving colump (head) up and down. It has 3 wires for 380V input, 3 wires to the motor, 2 wires for +24V and GND, and 1 wire - when 24V applied it is enabeling motor to one direction, another 1 wire - when 24V present there - motor is rotating in another direction. When 24V is present on both inputs - motor stops immediately. And most interesting for me was a purpose of one last wire "6" on schematic. On simulation, and later verified on my PCB, there is always nothing (0V), but each time after motor disabling there is a pulse of about 1sec of 24V. Hm... as I guessed and then discovered on the column motor there is built-in brake which is connected to this wire. So actually this is a break signal which is breaking motor immediately after input driving signal is disappearing ( together with disabling of voltage to the motor of course).

But this storry would not be so interesting without one more problem which I had with it... When i first time tried to insert my unlicensed copy of orange box ( I selected black box, I hope nobody will guess :D ), nothing happened, nothing was moving at all, and each time I tried i was receiving M504 error on the screen. After some time of suffering with PLC source code, I discovered that this error is appearing after some timeout. Time start when we press a button to drive column. And I was receiving this error almost instantly. Hm.... Next question was how much time we have? And I found answer - it is defined in machine parameter MP194. Its value multiplied by 20ms is a value if seconds of delay. And when I looked to my MP194 value ( i have a sheet of paper with parameters which was inside control box) - it was 0. So I had 0 second timeout to allow motor to drive anywhere... Nice... I've changed it to 2000 (=40sec) and ... and.. it start working just fine!!!! I was extremely glad, I spend so much time and efforts with this problem ( there was another story with hydraulic clamp) and finally it is working! During all my debugging of this issue I realized how really complex it is designed, but in the same time so clever, so many small details which were taken in account, these engineers put piece of their soul to this machine.
Many thanks to jz79, without your photos and efforts this would not be possible.
 

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Jenkins

Plastic
Joined
May 15, 2022
Meanwhile... Stromag CHA055 schematic extracted... (Without power board)
I think this device has been done by analog maniac
 

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jz79

Stainless
Joined
Mar 21, 2017
Could you please take a few pictures of the layout of the electrical cabinet on your machine? I guess it is bolted to the base, right? What does the inside structure going up and front look like from inside?

I want to eventually get rid of the separate electrical cabinet on mine and integrate everything like on the later machines to save some floor space and make it more ergonomic in general, I don't like that separate cabinet at all...
 

Jenkins

Plastic
Joined
May 15, 2022
I have also separate cabinet. Integration on\to the machine itself is not so bad idea, but it will not be easy task. A lot of wires need to be reconnected... Without full schematic of the machine i would not even think about it.
But I also saw such example on the second picture
 

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jz79

Stainless
Joined
Mar 21, 2017
ah, ok, I for some reason imagined yours is the latter one with the integrated electrical cabinet

the wiring isn't too complicated, and the wires are all marked, so rewiring isn't such a big issue, I plan to keep the back plane as it is in the new tall cabinet (that means less rewiring), and just moving the servo board rack and the Stromag drive to the other side above or below the "back" board, so the whole job is just shortening the incoming cables basically and getting rid of few plug connectors

something like this: (this one has a newer TNC control though)
3466693-11.1529484660__.jpg3466693-4.1529484660__.jpg slide-20068big.jpgslide-20067big.jpg
 

Jenkins

Plastic
Joined
May 15, 2022
I managed to repair spindle motor driver. I've manually tested almost all ICs - all of them were good. Then I started digging in the schematic and measuring voltages in different points, and found root cause - V103 had parasitic resistanse base-emiter and when measuring it in diode-mode it was showing 0.5V in both directions. After replacing it with new transistor (BC546) driver started working well. Without full schematic it would be very difficult to find root cause. I've updated a bit schematic in my post above.

Next question which I have - what is purpose of red digits led display on the right bottom on the control panel ? What i saw- it is turning on during TNC booting and then it is disabled after. What should be indicated there and in which conditions?
 

jz79

Stainless
Joined
Mar 21, 2017
if that display is like on my machine, then the 2 digit red 7 segment display is showing which tool number is currently programmed in TNC, and the bar is showing spindle motor load, that one may go to full when you start/stop the spindle, depending on how acceleration/deceleration values are set up in TNC parameters

that section on the control varies somewhat on some of these picomaxes, there is also a version that shows axis servo load also
 

Jenkins

Plastic
Joined
May 15, 2022
Servo load information can be extracted from servo drives boards. Voltage between pin 4 (signal value) and pin 3 (gnd) on bottom jack is proportional to the motor's current. If you wish - you can add voltmeters on the control box to display current load.
 








 
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