Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Robhi on May 08, 2013, 04:03:24 PM
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Hello every body,
I countered a problem as most of people on the web. I have wired my gecko 320x ( I guess correctly) as it mentioned in documents.
trimpot on 11 o'clock, I have done all the steps and every thing was going fine, testing the encoder, is OK too, sending pulses is fine too, till I have wired the servo motor,
kl 34 180 72. the fault led remains red. I have a power supply of 72 volt, ( bought a kit ) with the encoders etc...so normally everything is compatible.
any help would be appreciated.
thanks in advance
Thanks Robhi
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Where do you have the current limit pot set? One of the minor details Gecko has never bothered to document is that the current limit pot works backwards from the old G320, and normal convention - fully CCW is max current. I set mine up like the previous G320s, and got nothing but faults. Had to talk to two different people at Gecko before they told me that pot was bass-ackwards.
Regards,
Ray L.
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hi,
If you are talking about the limit trimpot, I have adjusted it as the P I D, at 11 o'clock, I tried at 10 o'clock but it is the same, always red fault red.
what do you mean by bass-ackwards? and how I could do the same as you?
thanks for your reply
Robhi
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Are Have you tried reversing the motor or encoder A/B wires? If the motor is not in sync with the encoder, the Gecko will fault on power-up. With all the pots at 10 o'clock, and no load on the motor, it should power up properly. Do you have ERR/RES connected to ENC+?
Regards,
Ray L.
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hello,
yes I have tried to reversing A/B wires but not the motor as red wire of the motor goes to + and black one goes to G, am sure of that.
and the ERR/RES is always connected to ENC+.
I will try to put all the pots on 10 o'clock and let you know...
there is no load on the motor.
thanks a lot
Robhi
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What kind of encoders are you using? G320X's don't really like USDigital Encoders - you must add pullup resistors on A/B, and disable encoder failure detection. They work very well with CUI encoders.
Regards,
Ray L.
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hi,
yes it is, I use us digital, but what kind of resistor should I use? how many K?
thanks
Robhi
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Reverse the polarity on servo motors. Just try it. I fought that same problem for a week. You can't hurt anything by trying it.
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hi,
yes it is, I use us digital, but what kind of resistor should I use? how many K?
thanks
Robhi
I don't recall the details, but there is documentation on the Gecko site detailing exactly what's necessary to make USDigital encoders work with the G320X. Personally I'd just ditch them, and get CUIs - they're under $30 each, and have selectable resolution. Mounting is identical.
Regards,
Ray L.
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hi,
yes it is, I use us digital, but what kind of resistor should I use? how many K?
thanks
Robhi
http://www.geckodrive.com/using-heds-encoders
Russ
:)
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OK.. I will try all what You have said... hoping it will be OK.. Let you know of course.
thanks for all you
Robhi
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Hi,
When I ordered the kit servo motor from keling, they sent 4 encoder, I guess old ones, one of the was damaged one the to me, then they sent me a CUIs encoder to replace it.
I tried it now and nearly every thing is OK, it works very well. and there no red led fault.
So many thanks for all of you.
But there is another thing, normally, with a powere supply of 70 volt, gecko 320x, KL 34, 180-72, of 4000 tpm, I should have a little bit speed. but I guess my motor is no too fast. current limit is set at 9h30 o'clock (lol). How could I have more speed if it is possible?
thanks again
Robhi :)
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It could be a few things, but this is most likely, with a servo there will be a rated RPM and also a rated voltage. The rated RPM can only be achieved if you supply the rated voltage.
So say it is 4000 rpm and 100v, but you only have 50v max then the max rpm you can expect from the motor will be approx 2000rpm.
Hood
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OK thanks Hood,
so when I have chosen the pulley of 20 teeth mounted on the motor and the other of 60 teeth mounted on the screw of 10mm pitch, it is a bad choice, I guess.
my machine is about 2500mm DE long, for wood, so it will be very slow. could I have an advice, if I use 30 teeth pulley mounted on the screw to have more speed?
what do you think?
thanks
Robhi
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Its hard to say whether you can gear less as I dont really know whether you need the torque that the gearing will give or whether you can get away with less.
Regarding the motors etc,
how many lines do the encoders have, possibly 500?
What pitch screws do you have?
What is the voltage of the supply you have?
What kernel are you using in Mach?
Hood
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hi,
Encoder 500 lines
pitch screw 10 mm
power supply 70 volt
kernel of mach3 35 000 k
thanks Hood
Robhi
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Ok just looked at the specs of your motors and the voltage constant is 18.95v/100rpm, I however think that may be a mistake.
Two reasons I am thinking that, first is normally the voltage constant of a servo is expressed as v/1000rpm and second it is giving a figure of 4000rpm at voltage constant, so if the 18.95/100rpm was correct then that would mean you would have to apply 758v to get that.
So we will take it that the specs are wrong and assuming you have a 70v power supply you should get in the region of 3,600rpm for your motors. With a gearing of 3:1 as you have then your rapid speed should be 12,200mm/min. (3600rpm/3 x 10)
However to achieve that rapid you would require a kernel of 2000 (500 x 4 encoder) x 3,600/60 = 120,000Hz or 120KHz
The max possible kernel in Mach is 100KHz but you will need a very fast and stable computer for that, more likely will be 45 to 65KHz.
So to summarise, to get the best out of your machine with that gearing you really need to use an external controller such as the SmoothStepper or CSMIO/IP-M etc as they will allow you to get the pulse rate you require.
Doing away with the gearing may allow you to get reasonable rapids from the parallel port, that will just depend on how much velocity you require and also what torque your machine requires.
Hood
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OK Hood, thank you so mach. But i guess it is so expensive to buy other materials, I will try to of what have.
thanks so much
Robhi
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What velocity are you thinking you will need?
Hood
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I am thinking to have about 30 seconds to achieve 2500mm.. but I guess I will never have it
Thanks
Robhi
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With the setup you have now then getting 5m/min would require a kernel of 65KHz (actually 50 but 65 the closest above)
So set your kernel to 65KHz , set motor tuning t 5000 velocity and restart Mach and see how it performs.
Hood
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Ok Hood, will try it hope it will be ok.
thanks too much
Robhi
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Just checked my g320x's re the torque trim pot.seems that the early 320 x's (3-4 years old)were more amps clockwise as the original 320/340 but there seems practically no difference where you position the pot on the recent ones (about a year old) although they do seem slightly stronger in the fully ccw position
Is there any more info on this,can anyone confirm my findings?
Tony
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Hello,
I tried as you told me Hood, 65kHz and 5000 velocity, it is nearly the same thing. on my ampèremeter it shows that only 5A that the motor takes.
when I put the current trimpot more than 11 o'clock I have immediately a short cut and the fusible comes down.
so what do you think if I mount the pulley of 20 teeth on the Screw and the other of 60 teeth on the motor itself for having more speed?
it will be OK or a very bad idea?
Robhi
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I have forgotten some thing, when the servo motor runs without the ground of the encoder it runs very fast, but mach3 of course does not control it. it runs only fast, one direction , that's all. I found it very strange. It should runs fast with mach3 too, (normally) so strange, is not it?
Robhi
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Can you attach your xml?
Hood
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Ok Hood, here it si
Thanks
Robhi
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Ok can you have a look on the diagnostics page, are there any limits active there?
What does the frequency say?
What does the Time in Int say?
If you go to the tab screen and press X+ what does the Units Per Min DRO read?
You seem to have a lot of axes set up, are you using all 6 axes? If so what for?
Hood
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Hello Hood,
first no limits active.
frequency is 62800
time in is about 5.9 to 6.1
when I press X+ unit per mi DRO is 4830
Axes are, I have a gantry, I will send you some pics, so 2 axes for Y, Y, Z, and and also A and C for turning Wood, but I guess later..
for now I am working with X axis if it will be OK, the all other axes will be the same
Thanks Hood
Robhi
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Ok that sounds fne regards frequency and time in Int.
Regarding the jogging, that also sounds fine as that is more or less what you have set for the X. Does the motor not turn at approx 1500 RPM when you are jogging?
Regarding multiple motors on axis, you should be slaving them, thats done from Config menu then Slaved Axis.
Hood
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yes I will have a slave one.
but there is a very important thing that I discover right now... normally, I have a pulley of 20 teeth on the motor, 60 teeth pulley one the screw. so, normally, If I write Go X 10.0 , the motor should turn 3 times, and the screw one time in order to have 10 mm, machine moves 10 mm since I have a screw of 10 pitch.
but I found that the motor turns 3/4 turn, even not one turn when I write G0 X 10.0 . so there is some thing that does not work in the step per unit I guess.
what do you think?
Robhi
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Your steps per unit should be correct at 600 if your encoder is 500 line and your gearing 3:1 with 10mm pitch screws.
I presume your X is at 0 when you command that X10 move?
Hood
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yes it was at 0
Robhi
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Not sure what is happening then unless the gearing or pitch or encoder count is not what you think.
Hood
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Hi,
I found some thing in the encoder that the DIP of the encoer were all of them at position 1, but in the pdf , manual of the encoder, 2 of them should be on and the position off.
I will try it and let you know.
Robhi
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Hello,
You are right Hood, the problem was in the encoder as you said. So I only changed the DIP switch of the encoder, adjusted the current limit of gecko 320x at only 9 o'clock and every thing is OK.. 3 runs to achieve 10mm , so it is correct now. and also the speed. now the motor turns so fast I guess more than 1500 rpm. so every thing is OK for now.
thank you so much Hood and all the other members of the forum.
thanks again
Robhi
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Good to hear you got it :)
Hood