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Denmark
397 Posts

Posted - 20 January 2014 :  23:50:35  Show Profile  Reply with Quote

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The new electronics for my CNC








Content:




I have now got the new electronics that I plan to use for my CNC



After using a long time on the internet looking for the best stepper drivers
and BOB (Break out board) then I fund an cool website in US called
www.cnc4pc.com there is making some good looking boards and seems to get some
good reviews on the net by users, the boards are clear and easy to understand
and looks to have a good build quality with through hole parts there is easy to
replace if the blue smoke gets out of some of them.
The drivers I got from a
web shop in Nederland called www.impulsecnc.nl/en/ there was having a good price
on the driver that I liked to buy, but more about this later in this blog.



#8195;
Primary BOB


This nice
little BOB called C35 from www.cnc4pc.com is the one that I plan to use to
connect to the stepper drivers to because it is just buffer driver there is
taking the weak signals from the LPT1 port and converting it to good 0-5 volt
signal so the drivers will get a nice clean signal and prevent them from lost
steps do to the weak signals from the LPT1 port there is in most modern PC’s.

The drivers are connected to this board via RJ45 cable for easy connection and
the other inputs will go via the screw terminals there is having a status led
for each input.
This board is not opt isolated but is connecting the signals
straight through to the drivers and this is because the drivers are having an
build-in optocoupler and there for there is no need to have the extra
optocouplers on the BOB also, because optocouplers are having a small delay in
the signal time and having more than one optocoupler can delay the signal to
much and give issues.
As you can see the boards are well build and easy to
repair if the blue smoke gets out and I like that very much in the design… not
that I plan to release the blue smoke.



Secondary BOB


I need a
secondary BOB in my setup because I will be using two LPT ports and the reason
for this is that I need more inputs then the 5 input signals that I can get from
the primary BOB, So this BOB will be configured as a input board there is then
giving me 13 inputs and 4 outputs, that will allow me to have all the signals
inputs that I need for limit switches and other sensors.
This board is not
opt isolated and that is a minor issue because I liked to have all the sensor
inputs isolated from the other stuff and to protect the PC, but I was not able
to find a BOB with the combo of having the many inputs and be isolated at the
same time, so I selected to use this board and then just make my own opt isolate
board with some 6N137 optocoupler and buffer drivers.
The board is called C10
from www.cnc4pc.com


#8195;
Stepper drivers


I have been
reading a lot about stepper motors and drivers to better understand what drivers
to select and what well fits well with the stepper motors there is on my CNC and
reading half the Internet, then I understand that it is better to run the setup
at high volts to better get the current to the motors so they can move better
and that the digital drivers are a lot better than analog drivers.
My stepper
motors are not easy to find the specs on because the label with the model
details a missing from two of the motors but I have seen the type/style of
motors before and know that it is a good brand motors but the model is unknown,
the last motor is placed inside the X axis motor housing and on it there is
model details on it, it is listed as an Vexta PH2610-E2.9 2.9A 1.16ohm 1.8degree
2 phase stepper motor.
So I am guessing that the two other motors may have
very similar specs.
The drivers that I have selected is the Leadshine EM806
there seems to be very good drivers, they are having this smart function where
you can connect an PC to the serial interface an then “program” the drivers with
some windows software there is coming with the drivers and with this software it
can also do an auto detect function of the motors there it is measuring the
specs of the motors and tune the driver to that, so this is very smart for me
when I don’t know the specs on the motors and it can then tell me what the specs
are and select the best settings for it.
For the voltages they are supporting
up to 80 volt and I plan to run with the voltages at around 60-70volt with the
current that each motors needs.
The drivers are also having stall detection
so if something prevents the motors from turning then the drivers will detect
that there is an issue and then stop running to protect the system from damages.

The driver is using a very fast DSP processer and can there for easily catch
input signals at up to 200 kHz and there for can run the system at very high
feedrate without losing steps.
So the Leadshine EM806 stepper driver seems to
be prefect for my setup and seems to be a lot better than the most of the black
stepper drivers that you can find on eBay.
I got my three drivers from
www.impulsecnc.nl/en/ there was having the lowers prices that I can find in the
EU.


Spindle RPM board


When I was
ordering the other parts from www.cnc4pc.com I then noted that they had this
little C3 index pulse board there is an “index pulse board”, it is using a small
optical sensor there is install inside the spindle and then the board will read
the RPMs of the spindle and send that as a impulse signal to the PC so the CNC
software will show the correct RPMs.
So later on when I have installed all
the other parts and the CNC up and running well then I will try to install this
little board.


#8195;
Buffer driver to fix controller issue.


Until I get all
the new parts installed on the CNC then I will still be using the cheap eBay CNC
controller there is on the CNC now and the issue with that is that is that it is
losing steps, so to make a cheap fast fix then I have got this little buffer
board from www.cnc4pc.com and what this little board is doing is to take the
weak signals from the PCs LPT port and make them into 0-5V signals and then
maybe get the eBay CNC controller to run better because it is now getting some
good strong signals.
The board only costs 20$ so if it can help the cheap bad
eBay CNC controller to run better until it gets replaced then it is a cheap fix.



So I got:
1 of CNC4PC C26 Output buffer board
1 of CNC4PC C35 LPT
Break out board
1 of CNC4PC C10 LPT Break out board
1 of CNC4PC C3 Index
impulse board
3 of Leadshine EM806 stepper driver


The CNC4PC boards I
got directly from www.cnc4pc.com in the US as I cannot find any shops there is
having them in the EU, so it cost me some import tax to get them into EU.
It
was positive experience to shop from CNC4PC as it was easy and fast, no issues.


The Leadshine stepper driver I got from www.impulsecnc.nl/en/ in Nederland
as they seems to have the lowest price in the EU and it was easy to shop with
them and the shipping was also fast.


Now that I got most of
the parts that I need then it is just to get them installed on the CNC, so I can
then get the bad EBay CNC controller removed and hopefully get a stabile CNC
there is not losing steps.
So looking forward to have a well working CNC but
I will keep you all update on this blog with the progress.













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