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Author Topic: Mach3, Delta ASDA-B2, ESS. 12 straight hours working on this. could use assist..  (Read 555 times)

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Hi,
sorry forgot to attach the picture.

Craig
My wife left with my best friend...
     and I miss him!
Morning! or whatever time it is in New Zealand!

I have ordered a transistor assortment off amazon. Should be here tomorrow or friday.

In the interim, I am going to pull a transistor off of some old defunct electronics. I think I have an old Zylotex board that has transistors.

Will see if I can dig one up for testing.

If, as I believe it is, relatively simple to get mach to talk to a servo drive (even though I have failed thus far, I can see it is very possible) then I cant figure out shy everyone has not adopted servos.

If a G203V costs 140USD, decent stepper costs 100USD and ESS cost 180USD, add to that a large DC power supply at 200USD, The stepper cost to drive one axis is 620USD. adding a 2nd axis brings the total up to 860USD. Not really cheap at all.

I can buy 2 new servos and drives for somewhere around 600USD, Add a ESS for 180USD, and the first axis costs 480USD, and adding a second brings the total to 780USD. Actually cheaper than the stepper setup.

At 3+ axis's the math changes to favor steppers. If cost minimization is the goal


If my math is even close to correct, their is no compelling reason to use steppers anymore. Servos are now affordable and seem to be vastly superior motors/drives.


Am I crazy, or am i seeing this correctly?

##################
Note that the internal 24V power supply is available at pin 17. Following the diagram you should direct connect pin 17 to pin 35.
With pin 35 now at 24V current can pass through the approx. 2kOhm resistor the 75 Ohm resistor, through the photodiode, through
the second 75 Ohm resistor to pin 37 and thence to the 24V COM at pin 14 via the transistor switch of your BoB or input circuit.
There is a second current path through the 2kOhm parallel resistor as well.

You can test the photodiode by having pins 17 and 35 connected as above. Then with your multimeter in ammeter mode probe
between pin 35 and pin 14. If the photodiode is intact I would expect a current of (24-2)/(2000 +75 +75)=10mA plus another
24/2000=12mA being the current through the 2kOhm parallel resistor, for a total of 22mA. If the photodiode is open circuit
you'll see only 12mA.
########################


Per your sugesstion above, I have used my cheap digital MM to check what I think is mA, on the meter it is marked 200m. this appears to be in the A_--- range. I am not positive about this, but this is the only setting which appears to me mA.

The range specs are here-
Specifications:
DC Current: 200μA/2mA/20mA ±(1.0%+2), 200mA ±(1.5%+2); 10A ±(3%+2)

wioth 17 and 35 connected (24vdc+ is present from drive pin 17) I have tried reading across pins 35 and 14,  and I get nothing until I hit the 200mA range and then the drive clicks, displays the drive model ASDAB2 on the drive screen. The meter appears to read 124 at this time, and as I continue reading it, the number starts dropping at a fairly quick rate. I suspect if I continued holding the meter leads in  place it might take a minute or two for the numbers to hit zero. Just a guess though, I did not test this theory.

by the way, the warning sticker that you referred to was on the drive. It looked important, but wasd not sure in waht way, so I stuck it to the dide of the drive for later use.

This brings me to the question of the resistors. I am not clear on where the resistors are in the real world. are the 2kohm and 75 ohm resistors contained in the asdab2 drive? thats the way the delta schematic and warni ng stiucker look to me, but I am really starting to suspect the resistors NOT contained inside the drive, but rather I must provide and hook them up external to the drive.

I really wish I had not read the CX-X wiring diagrams as having the resistors, diodes and transistors as being contained inside the drive. This is what happens when you have little understanding of electronics. But hey.. gotta learn somehow.


I was using wiring diagram C3/4, and the one you provided is C3/1. Glad to know I was suing the wrong diagram.

Looking at the correct diagram, the one you provided, it aopears that their are 8 resistors, 4 diodes and 2 transistors (if I read schematic correctly) I am thinking that these are not inside the drive. Am I correct in that?

The transistors look to be NPN. if I read the symbol correctly.

The diodes are either line diodes or photodiodes according to the way I interpret the symbols. I am thinking photodiodes as their has been discussion of them and if I have cooked them or not.

The diagram C3/1 also has a dashed (dotted) line around a diode and transistor, shown twice on the diagram, one for each for SIGN and PULSE. what is the meaning of the dashed line? does it denote something obvious to most, but that alludes me due to the fact that I clearly cannot read electronics schematics?



Additionally, if I am reading the symbol correctly inside the box marked controller on the drigram C3/1, it appears to show a transistor. Does not have the circle around it, but thats what the symbol looks like.

I am trying to wrap my mind around the "flow" of the diagram.

Looks like the diagram you created explains SO MUCH. I see how the resistors and transistors are wired now. YAY.
What value NPN transistor should I select for connection as shown in the hand done diagram you created?
Hi,

Quote
I have tried reading across pins 35 and 14,  and I get nothing until I hit the 200mA range and then the drive clicks

My apologies, I did specify pins 35 and 14, but I meant pins 37 and 14. By using a ammeter from 35 to 14 is effectively shorting the internal power supply
to 0V, please don't do it again. I'm hoping that the reducing current is an overcurrent limit device within the drive.

Follow the circuit of the picture:
pin 17= 24V output to pin 35, through the resistors and photo diode to pin 37, through you ammeter to pin 14 0V return.

Quote
This brings me to the question of the resistors. I am not clear on where the resistors are in the real world. are the 2kohm and 75 ohm resistors contained in the asdab2 drive?

Yes they are. My bum steer (pin 35 rather than pin 37) might lead you to believe they are not in circuit but if you retest but with the correct pin
you will 'see' the resistance. Again my apologies....measure the current between pins 37 an 14 for the direction photodiode and pins 41 and 14 for
the step photodiode.

I would not worry about transistors until you have established that the photodiodes are intact. Any small signal NPN transistor will do,
I used BC547's. Even a small MOSFET like a 2N7000 would work.

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

I hooked pin 17 to 35. and hooking my black probe up to pin 14, and the red probe (with meter in 200M scale) I get 22.8 from reading pin 14 to 37 and 14 to 41.

If I follow you correctly, I have just confirmed the photo diodes for SIGN and PULSE are operational, by finding 22.8 Mohms resistance across the internal resistors and photo-diodes.
I am thinking that if I now hook up a 1Kohm resistor to the output of my bobs step and direction pins, and then to pins 37 and 41,  then hook up my BOB's ground to the ASDA drives pin 14, I would have a way to test the drive again under Mach3 control.

Just checked, no dice. Did not see any response from the drive.

Thinking about all you have written and rereading it time and time again (thank you so much btw) I am thinking that if the photo-diodes are still working (believe verified) then possibly its that I am missing the transistors. because the drive does not want 5vdc signal. It wasnts 24vdc, or as close as I can get to that.

Seems to me their are resistors for current limiting to the photo-diodes, and resistors to act as the 'pull up'  then, and transistors are to amplify the 5vdc signal that is input into the ASDA drive. Then the ASDA drive 'sees' thew amplified voltage, if the voltage is in a range that ASDA will accept, then the drive will respond to the imput.

Do I have this somewhat correct?

What is the job of the photo-diodes? I am thinking they provide a means of insuring the pins 37 and 41 are unable to allow any current, signal or voltage from being accidentally output from the drives pins 37 and 41 and thus to the machine controller. I am also thinking that if their were a failure of the drive that could send dangerous voltage through 37 and 41(somehow), that the photo-diodes provide opto-isolation so that nothing can be output past the photo-diodes and out of the drive to the controller thus making things much safer. But hey, these are just my best guesses.

Thanks so so much for your input! I am grateful for your time and effort.