Created Date: August 27,2015

Created by: scott.lawrence

Hi.

First,i have very limited expirience with servos and positioning in particular.

What i need to do is use servo motor with external encoder to read position.

Since as i mentioned my expirience with these kind of things is limited i would appreciate a lot any info of how to approache this task.

is your application linear, or do you have X,Y,Z type axis positions?

A few details:

Position varies and should be entered either on HMI or on the drive itself if possible(to save on HMI).

easily done in the HMI, as this is the most practical way to enter new positions. Position data is easily saved in the PLC.

Also,can this application be done without external encoder (homing is not an option).

if the servo you plan on using has an internal indexer, you could use positioning as a home position , but may have some drift in actual position. An encoder will work better, but you could add a couple of prox switches for over travel in both directions and a home prox.

I still do not know all the requierments exactly,will know soon and let you know.Thanks.

the devil is always in the details.... and the details are the component properties & limits. We can tell you a million ways to make your application work in theory , but until the specs are known, it's all just guessing.

Created Date: August 27,2015

Created by: Slad

is your application linear, or do you have X,Y,Z type axis positions?

I got the details - it is a plate mounter used to install plates on printing cylinders (not sure if you familiar with flexo printing), for example the circumference of the cylinder can be divided into 1,2,3 or more equal zones (depends on how many "pictures " you want to get per 1 revolution of the cylinder when printing) so, what this servo is supposed to do is if say cylinder with 60 " circumference divided into 3 equal zones , operator will install 1st plate using physical reference on the cylinder, then presses button to zero the position (which I guess can be homing for a servo) and then presses another button to send servo 120 DEG or 20 " in circumference as per this example and so on.

Can AD servo drives do the job?

Thanks.

Created Date: August 28,2015

Created by: scott.lawrence

Can AD servo drives do the job?

absolutely, just depends on the programming.

I would recommend a Do-More & an H2-SERIO-2/4 or an H2-CTRIO-2, depending on which programming method you 're most comfortable with.

I prefer using the SERIO. I can write to the virtual I/O for enable, Home, and GOTO Position, and then read what the servo is doing, it's position, and it's status. If you 're using the internal indexer, you can write up to 8 consecutive positions, then command the moves via virtual I/O. See parameter 3-08 in the servo manual for a better understanding.

Created Date: September 27,2015

Created by: Slad

Hi.

Have a few more questions, i have 2 servo motors driving/turning 2 cylinders with different diameters(same config. as described above), both cylinders are slightly touching each other when moving,how can the system be configured to make sure that linear speed or speed of a point on circumference of both is always equal?

Thanks.

Created Date: September 28,2015

Created by: Slad

do you mean something like lead/lag?

are the cylinders fixed?

If I trigger for example 20 " move in circumference and the move takes say 10 sec, I need to make sure that at any given time they moved the same linear distance i.e. in 1 sec both moved X ", in 2 sec - XX " and so on.....or just imagine 2 cars need to get from point A to point B and the condition is that they should always be driving beside each other until arrive to destination.

Scott I am not sure what you mean by fixed,.. each journal has a supported bearing.

Thanks.

Created Date: September 28,2015

Created by: Tinker

Hi.

Have a few more questions, i have 2 servo motors driving/turning 2 cylinders with different diameters(same config. as described above), both cylinders are slightly touching each other when moving,how can the system be configured to make sure that linear speed or speed of a point on circumference of both is always equal?

Thanks.

Well, "electronic gearing " can do that, for certain values of "equal ". Some systems cam be pretty nearly "perfect " (but usually for a commensurate price) other systems may fall a little short of "perfect " but might still be "good enough ". Like I said, depends on the value of "equal ", but "electronic gearing " is the general term for what you are looking for, and I believe it is a common feature of many modern servo drives (SureServo's have it) and motion controllers.

"All animals are equal, but some are more equal than others "

Created Date: August 26,2015

Created by: Slad

Hi.

First,i have very limited expirience with servos and positioning in particular.

What i need to do is use servo motor with external encoder to read position.

Since as i mentioned my expirience with these kind of things is limited i would appreciate a lot any info of how to approache this task.

A few details:

Position varies and should be entered either on HMI or on the drive itself if possible(to save on HMI).

Also,can this application be done without external encoder (homing is not an option).

I still do not know all the requierments exactly,will know soon and let you know.

Thanks.