Messages

11

General Mach Discussion / Re: AC servomotor calibration problem

« on: September 01, 2017, 05:30:20 PM »

Hi,
sorry just rereading your post and yes all those sounds the servo is making are because Mach is not signalling the servo drive correctly, it probably
won't hurt the servo but its not how you want it to operate,

Craig

Yeah thats why i try out the smoothstepper now so i can get better and faster pulses

By the way, regarding the electronic gearing. Isen´t it what i already use when i via the software can choose step pr rev from a low number and up until those 65536 steps. Cant remember the precise number but if i what to set an ssi output from the driver i can go up around 1200 something, so maybe that is the number of the encoders output pr. rev

12

General Mach Discussion / Re: AC servomotor calibration problem

« on: September 01, 2017, 05:18:38 PM »

Hi,
sorry misclick...will carry on.
The faster you try to go the worse it gets. 25Khz is the common standard for most parallel port users. I have experimented with speeds up to 65kHz but
found it too unstable to be of any use and its not like my steppers need it anyway.

How can you solve this problem?

There are several alternatives:
1) Electronic gearing...just about all servo drives offer electronic gearing and in its simplest it means that if Mach applies one pulse to the drive
     it will get 'multiplied by 57', or whatever number you program into it... To take a extereme say you programmed in 65000 then one pulse from
     Mach would cause the servo to turn one rev. You could not however turn half a rev or some other fraction, ie electronic gearing costs you resolution,
     should that matter for a spindle?
2)Analogue voltage control....is there a reason that you selected step/direction, otherwise called position control for your spindle? If you intend to thread
   or require an indexing spindle for gearcutting maybe but in most cases just speed control is enuf. Just about all servo drives offer velocity control by
    application of an analogue voltage of 0-10V. Mach with a suitable breakout board can do this, most CNCers use analogue voltage to control the spindle
    speed.
3)Manual speed control...you could almost certainly have a pot or knob attached to you servodrive which controls the speed and then all Mach would
   have to do is turn it on or off.
4)Get an external motion controller...you mentioned an ESS, I use one and  it produces high quality pulse streams way WAY faster than a parallel port.
   I have a servo for my mill spindle, if I run it in step/direction mode (very unusally I might add) at full speed of 3500 rpm, ie 58 rev per second. The
  encoder is 2000 line or 8000 count per rev, ie at 58 rev/sec the ESS has to produce pulses at 467kHz without the use of electronic gearing. 467kHz is
   low AM band radio frequency! You need some flash signalling electronics to transmit pulses at that speed and your servo at the same speed will be
   58x65000=3.8Mhz. Within the ESS specs but only just and how you will signal your servo drive at that speed is a guess and could your servo drive even
   recognise a signal at that speed? The combination of electronic gearing and an ESS to bring the signalling rate down to a more reasonable 200kHz
   is indicated.

There  are some alternatives for you to think about....I would recommend you start by pursuing the simplest ones and later as your experience and/or
budget demands look at the  more ambitious (indexing) solutions. Analogue voltage and manual speed control are the simplest and ESS and/or electronic
gearing are the way to go for indexing operations.

Craig.

sorry wrote my reply as reply to my own thread, thats how it is when one is a newbie to this kind of communication haha

13

General Mach Discussion / Re: AC servomotor calibration problem

« on: September 01, 2017, 05:16:42 PM »

Hi,
sorry just rereading your post and yes all those sounds the servo is making are because Mach is not signalling the servo drive correctly, it probably
won't hurt the servo but its not how you want it to operate,

Craig

Yeah thats why i try out the smoothstepper now so i can get better and faster pulses

14

General Mach Discussion / Re: AC servomotor calibration problem

« on: September 01, 2017, 05:14:15 PM »

Hi and thanks for your answer joeaverage.

You are right about the encoder, i just couldn´t remember the excact number but you got it straight on.

The driver is a Bosch Rexroth DKC01.1-040-7-fw and the motor is a MKD090B-047-GG1-KN. The manual can be found at Bosch´s homepage, i have it but there is nothing about getting it to play within Mach3 or other like that.I have set the driver up with the software that belongs to this system so i am sure there is no errors there.

I think the only reason for the dro speed and actual speed is not the same must be because of the quality of the signal from the parallelport witch is changed to a differential signal with a driver called AM26ls31. I just ordered a smoothstepper today so i hope that will fix all of my problems at the same time.

I first set the step prr rpm to 200 cause this is what my steppers have too, but this made the motor really noisy and full of hard vibrations, and found out it gets better the higher i set the steprate. the 25 kHz is like you say not enough to get it running smooth cause the higher i set velocity=step pr rpm the lower the max speed gets, so smoothstepper and 4 MHz should fix that problem. Just hope the pulses is clean enough for my driver so the speed equals the actual speed. By the way is the only way to get an active "actual speed" by giving Mach3 a index signal from a proxy switch or similar. Again my mind tells me that in step mode what i ask for i s command should be precise what the actual speed becomes.

Whops saw you wrote more,,

I want to use step dir because then i can build a little bridge with a spindle so i can mill stuff like gears and put precise holes in a circular object, thinking i can use the spindle as a axis when i do this stuff. To begin with i also wanted this so i could do threading with total precision, cause mach3 would know precise were the spindle is all time and not only once pr rpm with in index way. Found out later that Mach3 was not even able to do threading this way, but still the axis need is there so fine with step mode. (maybe i have to give up upon it due to the vibration and noise but time will tell when smoothstepper is installed.

I am no electronic expert so sad to hear that i can´t even take advantage of the 4 MHz from ESS but i will look into what this electronic gearing is and were to get it/ how to build it.

I really appreciate that you take your time to help me out here. Thanks a lot.

15

General Mach Discussion / AC servomotor calibration problem

« on: September 01, 2017, 09:58:24 AM »

Hello all, i am new in here so i am not even sure this is the right place to ask, but here goes...

I am trying to setup a Bosch Ecodrive AC servo driver and motor as main spindle on a lathe. My problem is that when i try to setup this servo in motor tuning i can´t get the motor to run the actual rpm as i ask it to within mach3.

The servo is setup to work in step/dir mode, so i guess that it should be spot on with the rpm if correct set up. And by the way the actual speed on screen says 0, so do i have to install a tachometer setup even i use step/dir ?

Been reading different things about the value in velocity option, one is that this is the max speed the motor is designed for, another is that you need to take max speed and divide it with 60 to set the speed.

Tried both and neither is working. It runs but way off regarding the rpm. So anyone who can help me with this?

Another thing is that the motor is quite noisy and sounds like you can hear every single step. This gets better when i raise the step pr. rev. but to get the sound real good i would have to set it so high that mach3 can´t keep up and cuts down on the velocity. When i jog with the drivers internally jog button the motor does not make any sounds at all. Thinking to buy a smoothstepper to get more pulses because the servos driver accepts up to like 65000 pulses pr rev. Am i going in the right direction or is new controller overkill ?? ( i only use parallelport and bob right now.)

Also got a problem with changing in sound (like extra or missing clicks) from the motor, when i do as little as moving the mouse over the screen. I use a 2ghz desktop, os Win XP, and have disabled everything that does not needs to run. is the parallel setup this sensitive or am i having an extra issue here ?
 
Thanks in advance

16

Third party software and hardware support forums. / AC servomotor calibration problem

« on: August 31, 2017, 08:35:51 AM »

Hello all, i am new in here so i am not even sure this is the right place to ask, but here goes...

I am trying to setup a Bosch Ecodrive AC servo driver and motor as main spindle on a lathe. My problem is that when i try to setup this servo in motor tuning i can´t get the motor to run the actual rpm as i ask it to within mach3.

The servo is setup to work in step/dir mode, so i guess that it should be spot on with the rpm if correct set up. And by the way the actual speed on screen says 0, so do i have to install a tachometer setup even i use step/dir ?

Been reading different things about the value in velocity option, one is that this is the max speed the motor is designed for, another is that you need to take max speed and divide it with 60 to set the speed.

Tried both and neither is working. It runs but way off regarding the rpm. So anyone who can help me with this?

Another thing is that the motor is quite noisy and sounds like you can hear every single step. This gets better when i raise the step pr. rev. but to get the sound real good i would have to set it so high that mach3 can´t keep up and cuts down on the velocity. When i jog with the drivers internally jog button the motor does not make any sounds at all. Thinking to buy a smoothstepper to get more pulses because the servos driver accepts up to like 65000 pulses pr rev. Am i going in the right direction or is new controller overkill ?? ( i only use parallelport and bob right now.)

Also got a problem with changing in sound (like extra or missing clicks) from the motor, when i do as little as moving the mouse over the screen. I use a 2ghz desktop, os Win XP, and have disabled everything that does not needs to run. is the parallel setup this sensitive or am i having an extra issue here ?
 
Thanks in advance