some questions about configuration in MAX.

[leq_82]

Hello,everyone!

I have some questions about configuration in MAX(I am a jackaroo for motion control development),I hope I can get your help.

I use PCI-7344+UMI-7764+Servo amplifier+Servo motor,my MAX version is 4.2 and I use NI-Motion7.5

My question as following:

1,In Axis Configuration,for motor type,why I must select stepper but not servo?my motor is servo motor!If I select Servo,my motor can't run,I don't know why.

 If I select stepper,though motor can work but I can't test encoder in MAX.

2,In Stepper settings,for stepper loop mode,why I must select open-loop but not close-loop?If I select close-loop,the servo motor doesn't work too.

3,If I want my two servo motors run at different velocity,How shoud I do?It seems I just can set the same velocity in MAX for my two servo motors.

 My English is poor,Pls pardon me!I come from China.

Thank you for your help!

EnquanLi

[leq_82]

Hi,all

I have another question:UMI-7764 supports 4 axis,Does UMI-7764 support servo motor and stepper at the same time?I have two servo motors and two steppers.

Many thanks

EnquanLi

[Jochen]

EnquanLi,

could you please provide some more information about the drive and the motor type (vendor and model names) that you are using? If you can drive your motor in stepper mode I guess that your drive supports P-command mode but for now this is just a guess.
In MAX you can set different trajectory settings (velocity, acceleration, ...) for each axis but I recommend setting these values later in your application as most applications require flexible settings for these values anyway.

To answer your second question: Both, the 7344 and the 7764 support either stepper or servo motors with each axis.


I hope this helps,

Jochen K.
National Instruments

[leq_82]

Hi,Jochen,

Thank you for your kindly help!

The manufacturer of the drive and motor that I am using now is Japan SANYO DENKI,drive type is RS1A01AA,motor type is R2AA06020FXP00.

And I use position control mode,thehe encoder's counts per revolution is 131072.I set the electronic gear ratio to 1:1 for drive.

Now,I can use Close-Loop to control the motor but still has some problems.When I configure it to run in closed loop mode, the motors behave strangely and never move to the target position.When I configure it to run in closed loop mode, the motors behave strangely and never move to the target position.The detail situation is as following

1,Motor can't run.

2, Or motor moves to a position, then moves in the same direction agian and eventually stops.

Except for the  two points mentioned above,"Following Error" is  occured frequently,I don't know why.

I am still not clear why I must set the motor type be stepper in MAX .

And I have another question:what the relationship between the steps and the counts?They have the proportion relations?I notice that there are a section said like this in help document: For proper closed-loop and p-command operation, steps per revolution/counts per revolution must be in the range of 1/32,767 < steps/counts < 32,767. An incorrect counts to steps ratio can result in failure to reach the target position and erroneous closed-loop stepper operation.

I am verry sorry I have too many questions!

I am very appreciate for your kingly help!Thanks again!

EnquanLi

China

[leq_82]

I am looking forward to your help! I am very impatient.

[Jochen]

Sorry for the delay but I was searching for English data sheets for the drive and motor but unfortunately I wasn't successful as all of the websites that refer to the model numbers that you mentioned, are written in Japanese or Chinese.

At least I have found evidence that Sanyo Denki provides kind of stepper/servo hybrid drives (drives that control servos but that need pulse inputs like stepper drives). I guess that you are using something like that but I can't verify. I would be happy if you could provide me a link to English documentation for your components.

Still if my assumption is true, you can work with your system like with a stepper system and you should be able to find the answers to your questions here.

I hope this helps,

Jochen

[leq_82]

Hi,Jochen,

Thank you for your attention anyway!

I have a pdf document about Sanyo R series drive and motor,it's in attached file.

Just like you said ,the drive that I am using is a  kind of stepper/servo hybrid drive.(the drive type is RS1AO1AA,motor type is R2AA06020FXP00)

Now,I can run motor in close-loop mode but still have some troubles,they are sa follws:

1,the Follwing Error occurs frequently,the motor just started to walk a while then immediately to stop.If I disable this option,the motor won't happen like this again.

2,If I set the Pull-In Tries to it's default value(3),the motors behave strangely and never move to the target position.The motor moves to a position, then moves in the same direction agian and eventually stops.If I set the Pull-In Tries to 0,such situation won't happen again.

3,If I run the motor at a different velocity though the target position is fixed the distance that motor moves are difference.I don't why?

Looking forward four your answer,Thanks a lot!

EnquanLi

[leq_82]

Hi,Jochen

This is the attached pdf document.

[Jochen]

Unfortunately your attachment seems to be broken (I can't open it), but as you have verified the drive/motor type, I think it's not that important anymore.
The behaviour that you describe is typically caused by a mismatch of encoder counts/rev and stepper steps/rev. Have you followed the steps in the KB document that I have linked to my last post?

On the other hand I'm pretty sure that you don't need to run your motor in closed loop mode. As your motor is in fact a servo motor, the position control loop is already closed by the drive and it's really not necessary to close another position loop on the 7344. In your scenario the 7344 just generates the trajectory and the necessary pulses to output this trajectory to the drive. If your drive counts these pulses correctly (and I think you can rely on that), it's definitely ok to use the 7344 in open loop mode.

Best regards,

Jochen

[leq_82]

Hi,Jochen

You said it,I don't need to run my motor in closed loop mode.Now I am running my motor in P-Command Mode ,It's works prefect

after I disable the Following Error.I also think  the motors behaviour caused by a mismatch of encoder counts/rev and stepper steps/rev but

I don't how to adjust it. I have followed the steps in the KB document that I have linked to your last post but it still has those troubles.

How should I match of encoder counts/rev and stepper steps/rev properly?Could you recommed some documents for me?

Thanks very much!

EnquanLi