Yaskawa driver parameters

[riz]

Hi any help will be much appreciated,

I have been having trouble setting the parameters of my yaskawa drive SGDV-7R6A01A and AC servo motor SGMGV-09ADC61.

I am using sigma win+ software to interface with the driver.

I can jog the servo motor directly through the driver perfectly well but when I do the calibration in masso not so well. The travel distance of my pinion is 79.7964mm and I can not it that distance set.

Thanks

David

 

[breezy]

@riz

David,

I have been having trouble setting the parameters of my yaskawa drive SGDV-7R6A01A and AC servo motor SGMGV-09ADC61. I can jog the servo motor directly through the driver perfectly well but when I do the calibration in masso not so well. The travel distance of my pinion is 79.7964mm and I can not it that distance set.

Let's clarify where your problem is,

• Setting parameters in the Yaskawa driver
  
• Setting axis calibration in MASSO
  

If it is MASSO, grab a screenshot (CTRL + P MASSO dumps .bmp file into USB stick) of the axis calibration setup and upload it in your reply, so we can help you.

Regards,

Arie.

 

[riz]

Hi Arie,

I would say that it is both as i can't set the electronic gear ratio correctly in the driver (my gear ratio is 4 to 1). In masso I set the motor distance per revolution to the pinion travel and when I use the wizard it changes higher or lower depending on drive pulse per revolution. The encoder is 20bit 1048576 pulse per revolution. Most likely i am not understanding something.

Thanks

David

 

[evermech]

@riz

when you say your gear ratio is 4 to 1 do you mean mechanically on your drive?

If you are asking your driver to use an electronic gear ratio of 4 to 1 then I think you are saying for every 4 pulses put in by Masso put 1 pulse out to servo motor.

I had to use electronic gearing on my build to get some better speed from my servos as they are 10000 ppr encoders. At masso 's max output of 110 kHz p/s I could only get 11 revolutions per second - 660 rpm at motor shaft. I used a ratio of 1 to 4 which means for every 1 pulse Masso provided the servo driver sent 4 pulses to the motor bringing my rpm to 4 times faster. I think a screen shot as breezy suggested would be a good start point.

Guy

 

[riz]

Hi,

I will attach photos of the position parameter settings in the driver and axis settings in masso.

Thanks

David

 

[breezy]

@riz

David,

Hadn't forgotten you, it's just a case of finding time to read the driver PDF and understand it.

Now I need more info about your machine to be able to apply the info in the photos and the PDF settings for the driver.

• What is the mechanical drive arrangement. ie Rack & pinion, ballscrew.
  
• What mechanical gearing between motor and drive device. ie direct drive, gear ratio.
  
• What distance travelled for one rev of motor.
  

Going on the settings you have for Numerator & Denominator give a electronic gear ratio of 8.3 : 1 and if I have understood the PDF correctly MASSO's pulses per rev should be 262,144.

Regards,

Arie.

 

[riz]

Hi Arie,

Thanks for taking the time in finding out what i am getting wrong. Not a problem for the time.

• What is the mechanical drive arrangement. ie Rack & pinion, ballscrew.
  
• it is a rack and pinion on axis x and y with a pinion root diameter of 25.4 mm and ballscrew on the z axis.
  
• What mechanical gearing between motor and drive device. ie direct drive, gear ratio.
  
• It is driven by a belt, on the servo motor the gear has 20 teeth and the next gear has 90.
  
• What distance travelled for one rev of motor
  
• Is that the pinion travel distance?
  

Best Regards

David​

 

[breezy]

David,

• What is the mechanical drive arrangement. ie Rack & pinion, ballscrew.
  • it is a rack and pinion on axis x and y with a pinion root diameter of 25.4 mm
    
  • and ballscrew on the z axis. Ballscrew lead is?
    
  
  
  
• What mechanical gearing between motor and drive device. ie direct drive, gear ratio.
  • It is driven by a belt, on the servo motor the gear has 20 teeth and the next gear has 90. That gives us a 4.5 : 1 ratio. Does this also apply to Z axis?
    
  
  
  
• What distance travelled for one rev of motor
  • Is that the pinion travel distance? No distance carriage moves when MOTOR completes one rev. For X & Y axis approx 17.73mm please confirm.
    
  
  
  

For X & Y axis load the following into the driver

From 5.4.4 Electronic gear​

1. 1. Check machine specifications. Pulley diameter: 25.4 mm (pulley circumference: 79.79mm) Gear ratio: 1/4.5
      
   2. Check the encoder resolution. 1,048,576 (20-bit)
      
   3. Determine the reference unit used. Reference unit: 0.001 mm
      
   4. Calculate the travel distance per load shaft revolution. (Reference unit) 79.79 mm/0.001 mm=79,790
      
   5. Calculate the electronic gear ratio. B/A = 1,048,576/79,790 x 4.5/1
      
   6. Set parameters.
      1. Pn20E: 4,718,592 (Numerator)
         
      2. Pn210: 79,790 (Denominator)
         
      
      
      
   
   
   

Note that for these values to take effect a restart of the driver is required.​

and into MASSO set

• Distance travelled / rev = 17.731
  
• Pulses / rev = 59.13 This value seems low but if I have understood the PDF this is the result of the electronic gearing. Otherwise turn electronic gearing off and the value will be 605,763.
  

In 5.3.7 Setting Encoder Output Pulse Pn212 has a default value of 2048 but you have changed it to 31400 which is strange value as the common figures quoted are multiples of 16, any reason for this?

When you supply Z axis ballscrew value we can work out the setting needed there.

Hope that helps.

Regards,

Arie.

 

[breezy]

@riz

David,

Since I sent the previous reply I haven't been happy with the results, so I reread section 5.4 Position Control and I realised that I incorrectly calculated MASSO's Pulses / Rev value. I said it was low, that was because I miss interpreted step 4 of the Electronic Gear in relationship to MASSO's step output pulses. The EG requires 79790 pulses to rotate the pinion one revolution so MASSO's pulses / rev setting should be 79790 / 4.5 = 17731, you'll notice this is the distance travelled by one revolution of the motor divided by 0.001 which is the reference unit used in step 3 of the EG calculation.

Hopefully this explains things better for you.

Regards,

Arie.

 

[riz]

Hi sorry for not getting back to you earlier, i haven't had the time to work on the cnc. I have changed all the settings to what you have mentioned and pleased to say that it is working correctly. How I was setting the parameters in the driver was with the automatic set up wizard and that is how some strange parameters were being entered as well as i wasn't understanding how they correlated to each other and masso but how you set it out it has all come much clearer.

It seems to be travelling a bit slow when jogging. I can speed it up by increasing the max feed rate in masso but I am a bit concerned as the kHz in masso begin to rise as the feed rate is increased and I am concerned that it is going to push masso a bit more then it should. Is there a way to increase the speed in the driver.



Best Regards and thanks

David

 

[cncnutz]

Hi Riz

To increase sped without increasing Khz reduce your microstepping if there is a setting in the driver. If you are 16 : 1 change to 8 : 1 and the speed will double.

Not sure what Frequency you are getting up to but Masso will allow you to go to 110Khz maximum.

Cheers Peter

 

[breezy]

David,

It seems to be travelling a bit slow when jogging. I can speed it up by increasing the max feed rate in masso but I am a bit concerned as the kHz in masso begin to rise as the feed rate is increased and I am concerned that it is going to push masso a bit more then it should. Is there a way to increase the speed in the driver.

As Peter says

To increase speed without increasing Khz reduce your microstepping if there is a setting in the driver. If you are 16 : 1 change to 8 : 1 and the speed will double.

So if you change step 3

Determine the reference unit used. Reference unit: 0.001 mm​

From 0.001mm to 0.002mm will result in Pn210 = 39895 and Masso PPR = 8865.556 this should reduce MASSO's frequency and allow you to increase the feed rate.

Regards,

Arie.

 

[riz]

Hi, it has been awhile since I have worked on the cnc. All the settings that you helped me with worked perfectly.

Still need to calibrate the z axis still.

I have come to another problem, when jogging the machine on the y axis the slave axis seems to lose steps.

Regards

 

[riz]

Hi,

Today I was able to use the servo driver software interface to do some real-time monitoring. In one direction both y and b axis travel at the same speed but not in the other direction, b travels a little slower. At a loss.

Any help will be much appreciated.

Best Regards

David

 

[riz]

Hi again,

I have been tinkering and have noticed that the signal from masso to the driver on b axis slave is driving the the axis slower only during homing. With the driver interface i can see that the speed is only marginally slower on b axis during homing but when jogging they are the same.

My question is is it possible to change the signal to be the same as my gantry is quite rigid and would put undue stress on it. The difference is about 10mm to 15mm difference from when y axis hits home sensor to when b axis hits home sensor.

Regards

David

 

[breezy]

David,

During homing MASSO treats Y & B axes as independent axes, only in the sense of moving to the homing sensor. The calibration figures of the Y axis are used for both axes so there should not be any difference in the signals being sent to the drives. There could be microseconds delay between the signals as the processor calculates each axis in turn, but this shouldn't cause the slower signal you are seeing.

Once homing has completed the two axes are "locked" together with identical signals to each drive.

I know with my router there is fair bit of flex in the gantry and the Y & B axes can arrive at their homing sensors at different times, but the difference would be less than 5mm, depending how much the gantry has been pushed off "square" when it is powered down.

The only way I can see of you proving that the step signals are being sent at different rates is to get a dual trace oscilloscope and compare the two step signals. Lock one trace to Y axis and see if the B axis "moves" against it.

Regards,

Arie.

 

[riz]

I will try to get an oscilloscope to see. When I am logged into the drive via the software I only see a speed difference when homing. When jogging they arrive at the same time. If I jog the axis to the other end every time when homing it is out even if I do that procedure one after another. With no power down.

 

[riz]

Thanks for the help,

But I have another problem. I tried using the MDI command to start squaring X and Y and it will only take commands if it has a negative in front for example Y-200 and it will take it to 200 from the home position not 200 from the current position which is roughly in the middle of the table.

Regards

David

 

[cncnutz]

Hi Riz,

I did some testing and the B axis does seem to follow the Y axis when homing but once they have completed homing they do lock together and stay in sync.
It is only when they separate during homing that the B lags behind the Y.

It sounds like you have the Y axis setup backwards. Jog to the centre of the table and zero the Y axis. When you use MDI and enter Y200 it should move to the rear of the machine. If it moves to the front you have it set backwards. Correct that then set up homing.

This video explains the entire sequence to set up homing including checking the Axis direction and limits.

Cheers Peter

 

[riz]

Hi,

Thanks for that, it worked a treat.

In relation to how the B axis follows the Y axis is there a way to minimise the distance. As my gantry is very rigid, even when power is off and the bolts that secure the top of the gantry to the sides are tightened and i lean on it both sides move almost the same. So if one is following the other by 15mm it would put a great deal of stress on the gantry.

Is there a workaround for example to not tight the bolts as tight but that would bring it's own problems when machining.

Regards

David