Understanding MSO Instructions

[Bendanator]

Hello everyone,

 

I am new to the blog and this is my first post. I have taken on a new job and I do a lot more with plc's then I have ever done before. Question is, I have a machine that had a similar but wrong program downloaded into it before I hired on. I kept getting the ER bit on the MSO Instruction for the servo motor for axis 1 & 2. After going through the instruction I changed in the Homing tab the mode from Passive to Active and I can now run my Servo motor. Few questions would be that I have no clue the difference between Active and Passive and why this got rid of the ER bit on the MSO instruction allowing me to run.

 

just so you know the difference between the two machines is the one I was working on the servo motor had a two plug setup (guess is motor power cable and built in encoder cable. While the program came from a machine with a three cable hookup. The three cable is a added on encoder I believe( if it is a added on encoder why still hook up to the built in encoder)? on the other hand the 3 cable hookup I have had no problem with and that machine has run fine. Like stated before the three cable hookup was downloaded to the machine with a two cable hookup. Hope this message is clear and not to confusing. thanks  

 

 

[collinsd70]

Did you check the error code in the MSO.ER? 

Not that I can relate to your issue- but the code will give some useful indication as to the root cause.

The normal error I see is caused by a missing drive enable signal. 

[Bendanator]

Where do I access the code for MSO.ER? Is it in the instruction settings itself?

[collinsd70]

Hi Bendanator.

So if you 'monitor' your MSO Error Instruction in the Controller Tags- there is an INT inside the structure that will contain the last generated motion instruction error.

As long as you havent cleared the PLC Memory- this error code should still be stored in the controllers memory.

Please post the error number and I will feedback with further information. Where 'x' is the symbolic name of your MSO instruction- find 'x.ERR'.

Otherwise save a copy of your .ACD file and post here and I will check for you.

 

Regards

 

Daniel

Edited December 7, 2018 by collinsd70

[Bendanator]

If I am looking at it right the number for Motion.MSO(0)ERR is 40.  Thanks for your help.

[collinsd70]

40. You are trying to run a MSO or MAH instruction when the drive is locally disabled.

Could it be that the axis was inhibited at the time? 

This also could co-incide with the point I made previously regarding the hardwired enable to the drive missing..

In your MSO command...are you checking the contact x.DriveEnableStatus where x is your axis name? 

Edited December 7, 2018 by collinsd70

[Bendanator]

Not sure unless I just change it back. Sorry for not having more information this is my first time with Servo programming.The change I made. I clicked on the MSO instruction and went to homing tab and changed the homing mode from passive to active. By luck that made the servo ER clear. 

[collinsd70]

Okay- your logic should allow the x.ER bit to he reset somewhere, the important thing is your running again.

If you want me to take a quick glimpse over your code, feel free to send.

Regards

Daniel.

Edited December 7, 2018 by collinsd70