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Don't worry about this. I believe John is very experienced in electronics. Just go through it with one small step at a time.Quote:
. I very much welcome reading material to avoid pushing the limits of anyone.s patience. :)
Also have you disabled all the crap like screen savers and stuff in the bios that is not needed on the pc.
combining the circuit of one of the BOB outputs with the circuit f the stepper driver inputs :-
Attachment 24614
when the printer port or motion controller goes high
the output of one of the inverters in the 74HC14 goes low and
about 10.6mA flows through the opto isolators LED
the light turns on the NPN photo transistor that in turn pulls the
stepper driver negative input down to ground
(- step in the circuit example)
about 16mA flows through the stepper drivers input LED
the problem is when the BOB input goes LOW
the BOBs opto isolator LED is turned off but the NPN transistor takes a while to turn off
the square edge of the step pulse gets rounded off
delaying when the stepper driver LED is turned off
while I expect a faster opto-isolator is used inside of the stepper driver
the NPN photo transistor inside the drivers opto-isolator will further degrade the step pulse
John
PS
propagation delay through a high speed opto-isolator
Attachment 24615
not only is the signal delayed but the edges are rounded - see page 4
PPS
in another thread to use surplus Tormach stepper drivers
https://www.cnczone.com/forums/torma...ml#post2107952
from the above post
Attachment 24616
you can see the Tormach / Leadshine stepper driver uses a HCPL 2531 dual high speed opto isolator for the step & direction inputs
a slower FL817 opto-isolator being used for the enable input
the "817" being the opto-isolator I expect your BOB to have
Clive: yep, no such thing on this 12+ years pc, has a built in parallel port, windows 7 32 bits, no aero theme or screensaver. I don.t know what are the bios things which I don.t need.
John: ok, got the point a light and a sensor which acts like a switch and this one does not work fast enough. Now changing the drivers (wantai) is not possible, and buying others costs a bit.
Changing or upgrading the optoisolator in drivers or bob is I guess problematic. Like chancing the tiny chip on a pcb, is doable, and I have some tools for that, but not the skills just yet.
I can buy another Bob, if it helps. Should I, and if yes, which one?
I would try another BOB that does not have opto-isolated outputs
and either has 74HC14 HEX inverters connecting the printer port outputs to the stepper driver inputs or 74ACT245 octal transceivers as used on the C10 BOB
Attachment 24617
the C10 has no opto-isolators on either the inputs or outputs
note this BOB
Attachment 24618
has a design flaw
if you look at the 74HC14 used for the inputs
the supply pi 14 is not connected !!!
see top left hand corner of the circuit diagram
Attachment 24619
John
Has the enable been connected up yet ?
I would common all the +v inputs to the drivers and use -ve pulses to drive enable, step and direction. There again, I wouldn't use that BoB as it has no relay output (though these can be added with a cheap board) and no 0-10v speed control.
I happily use this board https://www.dropbox.com/s/gfq4isvihn...rd-EN.pdf?dl=0 and have only blown one of them so far (my own stupid fault). At least they are cheap :untroubled:
I found both ones available in my area, 22 euro for db25 (with relay), and 30 euro for the C10 (if it works with that flaw)
Also HDBB2 at apx 50 euro https://www.ebay.com/itm/HDBB2-break...sid=m570.l1313.
So I.ll get any of these, now the tricky part is which one?
Also have available UC300ETH, but it is expensive as hell, apx 150 euro
Like this;- https://www.ebay.co.uk/itm/5-CNC-Axi...4AAOSwaxlZiq98Quote:
Originally Posted by Radu_Andrei
These boards require 5v and 12-24v for the inputs and speed control to work
You can buy them from China as well:- https://www.aliexpress.com/item/5-Ax...ceBeautifyAB=0
Probably shipped from China (their Engrish warehouse).Quote:
Originally Posted by Clive S
this BOB
https://www.ebay.co.uk/itm/5-CNC-Axi...4AAOSwaxlZiq98
is the type of BOB I would use
Attachment 24620
it looks like its a version of this BOB found in some control boxes supplied with some 6040 CNC machines
Attachment 24621
the TX14175 has the advantage of having a 5V to 5V DC converter to provide the isolated 5V supply for the 75HC245's
instead of taking a 5V supply from a USB port
the HDBB2 looks good
I am not sure why they have used a expensive 36 way centronics connector instead of a 25 way D-type connector
John
Ok. Thank you. Will order today. :)
Hi again.
I.ve build the metal box and reorganized everything, and wired the new Bob. It seems the motor problem has gone, but will post a video soon and let you be the judge of that.
Now, I.ve wired the Bob like in the photo attached, and I.m not getting any response from the input pins, from none. P10 to 15 are not seen in automated setup in mach 3.
I should know the answer from the first picture from post 49, but the truth is that I don.t. :(
What am I missing?
Attachment 24648
If you are using the BoB in the picture, you will need the 12-24v input to work the LEDs in the output opto-isolators. It looks like you have a fault there. Also check that the GND connections are all together, except for the PC ground.
the USB cable powers the two 74HC245 octal buffer IC's that connects the printer port outputs to your stepper drivers
the 12 to 24v supply is required to power the five input opto-isolators
& the PWM to 10V analogue converter that's controlled by pin 1
Attachment 24650
when a switch grounds an input current flows through the opto-isolators LED so the NPN photo transistor is turned ON
so the corresponding printer port input is grounded
when the switch is tripped and opens
the printer port pin goes high
(set pin as active high in mach3)
Attachment 24651
John
It has the 12 v input, a light is on on the bob at the end of the input pins. It makes a subtle high pitch noise when I connect any of the input pins to the ground pin, but it does not register it in mach 3.
All grounds are together, but now I.m testing it with a single wire.
Pc gnd is not connected to anything.
The only difference with this bob is that it has a P14, to which all I ran all ENBL- from the drivers.
does it still make a noise if you remover the jumper to disable the relay ?
(I can't think of anything other than the relay that could make a noise)
having a quick look at the data sheet for the LM317 regulator
the 12 to 24V DC supply needs to be a minimum of 13.5V
the supply goes via a diode that drops about 0.6V and the LM317 regulator should have an input that's at least 3V more than the 10V output
is the 12V supply regulated ? or is it unregulated and is more than 12V if lightly loaded
for your initial tests you can disconnect the connection to the stepper driver enable
John
PS
a simple input tester I used to test a similar BOB without using a PC (or motion controller)
Attachment 24652
So you are using a USB cable from the PC?Quote:
Originally Posted by Radu_Andrei
the supply is a 12v transformer, which used to power up some car led.s strips. the multimeter reads 12.1 v. it is the one i use for the enclosure fans.
as i fiddled with the wires, somehow it works now. probably a bad connection from the 12v supply. so Thank you!
I looked a bit online, and the eccomerce webs in my country have plenty of 12v, but no 24 supply. Surely there might be some specialized shops somewhere.
It works like this now. Do I ask for trouble if I don.t use a higher supply, 13.5v and above?
Now on the other side of the bob, for spindle control via mach 3, from what I understand, the gnd pin goes to ACM, the 0-10v to V1, 1st relay pin (5th in order) to DCM, and 2nd relay pin to FOR.
Is this correct?
Attachment 24653
great to see you have it working even if your not 100% sure which connection you re-made during your investigation
your connection to the VFD looks correct
in practice using the 12V supply probably will work
while the LM317's data sheet gives the minimum supply voltage as V out +3V this will be the worse case accounting for the production spread in the IC's parameters
even if the supply is too low for the regulator to regulate the output as intended
the fact you have a regulated 12V supply
the voltage is likely to be near to 10V and not change too much and
cause the calibration of analogue control voltage to the VFD to vary
John
I have another identical supply, so wiring it in series might give me 24v, or 20 due to what you said. I might have a spare laptop charger somewhere, which is 17 or 19v.
If it is a requirement, I.ll do it.
Thanks again for the detailed answer. :)
Leave it alone at 12v - if it ain't broke, don't fix it. If you get 0 - 10v on the analogue output, you'll be fine.Quote:
Originally Posted by Radu_Andrei
Ok. Thank you. And yes, the 5v usb cable is run from the pc. I have a phone charger available as well. It reads 4.74v at pc5v and pcgnd.
Does it matter?
phone chargers are not regulated very well
so you will be better off either using the PC's USB port or using a regulated 5V power supply to power the 5V side of the breakout board
John
Quote:
Originally Posted by john swift
I made Attachment 24654a pass-thru tester years ago when I was trying to work out what was happening with a printer/plotter I had. Exactly the same as that but with lower value resistors but each LED was powered by the printer or PC.
I use exactly that BoB with a 12/5v dual power supply from a defunct external hard drive. It works fine !Quote:
Originally Posted by john swift
What voltage do you have between an input pin and ground with out any switch connected?Quote:
Originally Posted by Radu_Andrei
Hi.
Sorry for the late reply, the internet was out for a while.
Nice tester. It seems you guys are doing this electronics thing for quite some time. That.s why you.re all so smart. I suspected at first, that you.ve made a pact or something, like Faust, that you knew the answer to every problem I came up with. :P
Regarding the question, if I remeber right, as I measured a lot of connections today, I don.t think it was any voltage between the input pins and ground, but I might be wrong. I.ll check tomorrow, if it helps.
It seems ok so far how the project is going. I just finished a few hours ago to install the touch plate, added some script in mach 3, and it seems to work ok but a bit slow. I.ll change some numbers in there and should be fine.
Next week I.ll set the soft limits, reconnect the x and y motors to the ballscrews, and run some tests. I don.t know, what test I need to check if I get steps missed, but at least I have a plan. :)
Then add a flat wood surface and make it straight, mill it I guess, then add a sacrifice board on top of it, then learn some cam software, and also buy some ebay projects with sculptures and stuff, to have a go at cutting.
I don.t know if all this ideas are good either, but thanks to you guys, I kinda feel confident it will all work just fine.
There.s still quite some work to do, and I.m aware I.ll keep bothering you for some time, but still... A BIG THANK YOU to you all. :)
You mean a lot for people without technical backgrounds. A couple decades ago, people were struggling to find info like this, and most of the time they could not.
I have more gratitude to express, but I.m starting to sound creepy, so I.ll shut up.
If you have connected 12-24 v to the centre two terminal on the bob you should have about 7-12v on the input pins.Quote:
Regarding the question, if I remember right, as I measured a lot of connections today, I don.t think it was any voltage between the input pins and ground, but I might be wrong. I.ll check tomorrow, if it helps.
if you have not got any volts on the inputs pins then you might have burnt the pcb track out on the board. I have seen this in the past.
So just get one thing at a time working. Those bobs although cheap I find to be quite good.
Hi.
I just measured it, with and without the limits connected, and I get 0v between GND and all pins except P13, at this one I get 26v. P13 happens to be the probe, but I disconected the cable, and same reading.
I don.t know how I could have burned anything, as I just run the usb cable from the pc, and the 12v supply.
Yet the limits, estop and probe work fine. No more false signals. :)
P.S. although the vfd is not connected just yet, on the bob I get 2 light on all the time, the 5v and 12-24v leds, and sometimes the relay led. It does not stay lit all the time. I don.t know if that.s bad or not, I just thought I should mention it.
Does this mean that all is working OK?Quote:
Yet the limits, estop and probe work fine. No more false signals. :)
I am not sure why you have 26v on P13 !!
there must be a detail we don't have to explain why you measure 26V on input P13
which terminal did you connect the volt meters negative probe ?
Attachment 24657
the printer port ground is connected to the mains supply earth / ground
on the other side of the BOB's opto-isolated circuit
the 5 inputs can not be more than +10V more than
the 12-24V supply ground , input ground & analogue output ground
(which are all connected together on the BOB)
depending on the 12V power supply your using the 3 grounds may be at a different potential to the mains supply ground
small switch mode power supplies such as the ones used with laptops and other IT equipment don't have the negative output terminal connected to earth like PC AT or ATX supplies
they have a small capacitor bridging the mains input & DC output !!!!
( the capacitor is a backwards step just to comply with EMI requirements)
the leakage from a couple of devices is OK but several power supplies can add up to give you a shock
John
PSAttachment 24658
What I mean that all seems ok, is in comparison with the last state of the machine when the motors were going nuts and the limits were switching erratically.
The bob is not grounded by any individual cable. I assumed that via the usb cable, a ground is provided, which goes to the pc case, and then to the mains.
I did not measure the ground from the mains, but when I touch it, it gives a tingling sensation, like is has some voltage going through it. This is the mains earth as it comes into the property.
The bright side is that it.s all better than before, so I.m still happy, even if, righfully so, Clive disagrees with my so called ˇˇall okˇˇ opinion. I.ll rephrase that. All better than before.
Perhaps we have a difference in language. By "working OK" I meant that are the inputs now working as intended , ie if you connect one of the inputs to ground does this show that it is triggered in Mach3 ?Quote:
The bright side is that it.s all better than before, so I.m still happy, even if, righfully so, Clive disagrees with my so called ˇˇall okˇˇ opinion. I.ll rephrase that. All better than before.
For the avoidance of doubt when we ask for a voltage measurement between an input and ground we mean between the input pin and -ve of the power supply (not earth star point).
Do you get the tingle sensation when you touch the star ground point.
Hi Clive,
Yes, all 5 input pins are triggered in mach 3.
The measurement regarding 26v (right now is 24v) was taken between p13 and the gnd situated right next to p15.
Last week, when I connected the control box to the mains, I.ve cut power via the workshop fuse, and wired everything up, but the earth wire does not go through any breaker, switch, fuse etc, it.s go directly into the mains street pole.
On that particular time, it was raining outside, and when I touched the earth wire, it felt quite unpleasant. Touching it now for example, I do no feel anything. I.m taking about the yellow/green continuation as a single wire of the star ground point.
P.S. measuring between -12v on the other side of the bob, and the p10 to 15, I get the same readings, measuring the +12 v and p10 to 15 I get 12v into all pins except p13 which has 16v.
Is this the -ve fro the power supply? the - pin of the dc12v?
It seems that you may have a poor earthing of the mains supply. If you get any voltages on the earth from the pole, you may have a bad /corroded connection somewhere outside.
I cannot fix anything out there. I can only disconnect the earth mains wire, and instead add an diy one, like drive an iron rod into the ground somewhere outside. Is this good enough?
An iron rod will corrode quickly, earthing rods are brass or copper.Quote:
Originally Posted by Radu_Andrei
I don't know how things work in Romania, but in UK Electricity supply safety is taken seriously. I would ask a qualified electrician before doing anything.
Back here the hardware part of electricity supply is from the time of communism, E-on just bought the old national company, but did not upgrade anything, at least not in the village areas. Well, they.re still changing the main fuse/clock boxes at some houses today, as there still are properties with ceramic fuses.
So if you.re nostalgic and what to see how was life in the Uk 50 years ago, come over. Maybe even longer than that.
We have some spanish family friends which visit us now and then and they always point out activities going on here, which were present in their country in the 70.s.
The whole eastern block is like this, but slowly we.re catching up. Looking forward another half century, you.ll be able to drive a car here, while being sick of the spaceships you.ll have in uk.
Now back to the problem, if the issue is inside my property, I assume an electrician could change some cables and so on, but they.ll not change the whole electrical infrastructure for me. :)
I doubt that the problem in on my side, as the whole residential wiring was done 3 years ago brand new.
I.ll ask anyway to see, maybe he has some kind of solution.
I.ll post a video very soon with some axis movements to see what you think.
I can't see a problem if you could drive an earth rod (copper) into the ground external to the property and connect that to the earth coming into the building.Quote:
On that particular time, it was raining outside, and when I touched the earth wire, it felt quite unpleasant. Touching it now for example, I do no feel anything. I.m taking about the yellow/green continuation as a single wire of the star ground point.
https://www.tlc-direct.co.uk/Product...xoCHl0QAvD_BwE.
Glad to hear you have finally got it working.