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Author Topic: Mach3, Delta ASDA-B2, ESS. 12 straight hours working on this. could use assist..  (Read 628 times)

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Hi,
just to confirm you are using the 200mA scale. The measurement you are taking has nothing to do with resistance, its a measure of
current.

Usually there are three, maybe four input sockets on a multimeter. The Com, is the black one. The V/Ohm red one is to the right.
The two current input terminals are to the left, one (fuse protected) is up to 200mA and the other, depending on the model is not
fuse protected and up to 10A

One multimeter lead should be in the COM socket and the other in the 200mA socket with the selector dial on 200mA DC.

It sounds like you are reading 22.8mA, which is good news as it suggests that the photodiodes are intact.

Just as a comparison please put the multimeter lead from the 200mA socket to the V/Ohm socket and with the dial set to 20kOHM
measure the resistance between pins 35 and 37 with the drive de-powered. I would expect a shade under 2kOhm.

Craig
My wife left with my best friend...
     and I miss him!
Hi,

Quote
Do I have this somewhat correct?

No you don't!. Delta drives are INDUSTRIAL grade, they are intended for 24V inputs, excepting differential modes.....but we are not talking
differential modes here.....we are talking single ended.

Your BoB is 5V output as is common with hobby grade controllers...and a 5V output is not going to work on a drive that is expecting a 24V
input. That is the true purpose of the discrete transistors in the diagram that I posted. The 5V bob output via a 1k (approx.) resistor to the
base of an NPN transistor will be any amount enough current to turn the transistor hard on. The transistor when conducting hard on will
cause the current to flow from pin 37 to pin 14 and thereby illuminate the photodiode.

You need six transistors, say BC 547's and six 1kOhm or 1.5kOhm resistors for a three axis machine. You could alternately use 2N7000 MOSFET's
which would not require the 1kOhm resistor to make it even simpler. I would recommend a little vero-board or similar to solder it together.

Craig
My wife left with my best friend...
     and I miss him!
Hi,

Quote
No you don't!. Delta drives are INDUSTRIAL grade, they are intended for 24V inputs, excepting differential modes.....but we are not talking
differential modes here.....we are talking single ended.

I'm sorry I've just re-read your post and YES you are correct, the transistor I have depicted allows your 5V BoB to turn on and off the 24V
photodiode circuit.

Craig
My wife left with my best friend...
     and I miss him!
Checking the Resistance withg the 20Ohm scale on my meter with Com correct and the Red probe connected to the 200mA, when I check resistence I get 1.28

I think this is in line with your prediction of under 2Kom
Hi,
the photodiode is part of the opto-isolator of the pulse input circuit of the drive. When the photodiode is illuminated the phototransistor
is turned on and a pulse is signalled to the drive. Note that it is light signalled, there is no electrical or galvanaic connection to the internals
of the drive. This is to prevent a voltage mismatch at the input damaging the drive logic and microprocessor. That terminals provided
to the photodiode allow for included resistors when using single ended 24V signalling and much lower resistance (50Ohm approx.) when
using 5V differential signalling.

The only downside of having the two options id that you could miswire the inputs and therefore apply 24V to the photodiode WITHOUT the
benefit of the larger (2kOhm) resistors and thereby damage the photodiodes.

Believe it or not single ended signalling is much easier to understand and implement....and you should definitely do that BEFORE you attempt
differential signalling.

Craig
My wife left with my best friend...
     and I miss him!
Hi,

Quote
Checking the Resistance withg the 20Ohm scale on my meter with Com correct and the Red probe connected to the 200mA, when I check resistence I get 1.28

I think this is in line with your prediction of under 2Kom

This does not make sense.

One multimeter lead should be in the COM socket and the other lead in the V/Ohm socket with the dial set to 20 kOhm scale. Please repeat the
measurement and confirm the connections to your meter.

Craig
My wife left with my best friend...
     and I miss him!
So, looks like the photodiodes checkout. I have rechecked my multi meter porb connections and made sure its set up to measure current. set to 200m on the dial, With the drive enabled, pin 17 connected to 35, and connecting the black porobe to the pin 14 (common), and the red probe to pins 37 and 41 respectively, I get readings of 22.5mA

I have done as you suggest here-

"Just as a comparison please put the multimeter lead from the 200mA socket to the V/Ohm socket and with the dial set to 20kOHM
measure the resistance between pins 35 and 37 with the drive de-powered. I would expect a shade under 2kOhm."

I using the 20k ohm setting. I get .88 measured between pins 35 and 37.
Does it appear to you that I have not toasted the photodiodes? given the measurements I have listed above.

My apologies. I think I was mixing up A and O because I was skiping around so much trying to wrap my head around things. thus creating confusion for you that was unnecessary. Rest assured that I am doing my best to not waste your time and am not trying to be lazy and just ask for everything done for me. I am so happy that I am finally learning this stuff. Its been a dream of mine for years to understand things like resistors, diodes, transistors, timers, ics, etc. I only know enpough to be dangerous, but whole heartedly want to get to a place where I am proficient in basic electronics, plc's, servo drives, communication etc. My strongest interest in life is machine tools (particularly Parker Majestic, Moore and Monarch) so understanding the electronics operating everything and how they do it will give me a better understanding of the whole thing. I get the mechanical side of things fairly well. I can correct geometry with scraping and rebuild spindles and such, but have onle ever had a vauge understanding of how 'real' machines work.

Hobby control I am familiar with. Running industrial controlled machines I have done, but knowing how the industrial machines work is a whole other level of understanding I have a strong desire to achieve.



BTW, I was careful not to short out the internal 24dc like I did before. I thought the clicking sounded 're-set-ish' and so I pulled the meter leads after short observation. fortunately the protective circuitry appears to have saved me.

Hi,

Quote
Does it appear to you that I have not toasted the photodiodes? given the measurements I have listed above.

No, I think they are OK. Delta is a good brand and while its not impossible to blow them up they are well designed
and do not fail as a result of the usual misadventures they suffer.

Quote
BTW, I was careful not to short out the internal 24dc like I did before. I thought the clicking sounded 're-set-ish' and so I pulled the meter leads after short observation. fortunately the protective circuitry appears to have saved me.

I agree, and am glad because it was my mistake the induced you to do it. I think this is a case in point of what I mean above. Delta has made design
provision that the supply could be shorted WITHOUT causing failure where another cheaper brand may not have.

Delta drives are not hugely expensive but I'm sure I don't want to damage mine any more than you wish to damage yours, so it behoves
us to be a little cautious about wiring them up.

I will draw a circuit diagram that may hopefully clear up some of the confusion.

Craig
My wife left with my best friend...
     and I miss him!