Motion Servo Controls – Part 1

To start out with here is an introduction to what you can expect from this RSLogix 5000 training section. This section will be going over RSLogix 5000 servo controls and how they work from the very start of beginning a program to more advanced features such as understanding how to take a rotary axis and configure the conversion constants for a rollover. In the beginning, it will start off at making a program and showing some of the features there are to aid in motion axis direct commands.

Here is a direct link to my full servo video library on YouTube – Click here Shane Welcher – Servo Controls

In this first video, I will show you how to set up the beginning features such as the time synchronization along will with adding a motion group with a few virtual axis servos. This video will also be talking about the standard communications cards that are used to be able to have the RSLogix 5000 processor to the servo controller that you are using, either a sercos system or CIP motion.

I explain the properties of the motion group to give a good understanding of the course rate update time and the auto tag update feature for that motion group showing how to calculate the time of the course rate update.

Here is video #1:

Video one is only about 14 minutes and most of the videos except for the very last step, it is important to watch the whole video of each step to get the best understanding of a servo system.

Motion Servo Controls – Part 2

In video 2, I will be going over the motion direct commands from the axis themselves while explaining the commands and the standard operation of how the proper sequence of a servo system from the standpoint of how to do a shutdown reset, a fault reset, an off command, a on command, a home command, along with the showing how to jog with the motion axis direct commands. I also show the do basic setups for axis dynamics. Setting the dynamics of a servo is critical to be able to run that servo and also sets how fast that servo will run.

This shows the virtual axis in a running state using the motion axis direct command along with showing how to set your tags in the controller to a structured format if you are an RSLogix 5000 version of 18 or higher. I explain how a servo works when you home it and also the difference in a home and a position redefine, also a home with an offset.

Here is video #2

Video one is only about 15 minutes and most of the videos except for the very last step, it is important to watch the whole video of each step to get the best understanding of a servo system.

Motion Servo Controls – Part 3

In video three I show a simple control scheme to show how to program the logic for a servo system to run in a simple state machine. This will show how to get a servo axis reset out of a motion axis shutdown status to be able to go to a state where it is able to be homed. Once it reaches axis homed status then use index a MAM instruction which is a motion axis move instruction to a position of 500 units, when the servo counts reach 500 units then it will allow a jog function. This does show the servo running by looking at the servo’s tags in the controller tags

I also explain what the instruction bits are used for and what they stand for such as:

  • .EN
  • .DN
  • .ER
  • .IP
  • .PC

These bits are used to transition states for the proper control of a servo. To better explain the states of this video here is a layout of what each state allows:

  • State 0 is the system inactive and the axis is shutdown
  • State 1 is the axis out of shutdown status and ability to be homed
  • State 2 uses a MAM instruction to move the servo to a position unit of 500
  • State 3 the axis is at a position unit of 500 and now gives the ability to jog the servo axis
  • State 4 monitors if the job pushbutton is not pressed and if it is not then it stops the MAJ or motion axis jog from state 3, after the MAJ is stopped then it transitions back to state 3 to be able to be jogged again if needed.
  • At any time if the shutdown button is pressed then it will shut down the servo axis and move the system to state 0

Here is video #3

Video one is only about 15 minutes and most of the videos except for the very last step, it is important to watch the whole video of each step to get the best understanding of a servo system.

Here is video 3.5 to give a more in-depth look at what the motion instructions are and what they do, while also showing why the instructions are set they way they are.

Motion Servo Controls – Part 4

In part 4 of motion controls, I will be showing how to control speeds of a servo using a MCD instruction which is a motion change dynamic instruction. The servo does not need to be stopped to be able to change speeds using this command. Fully explaining how to use the MCD instruction by using a simple theory of an update tag feature from a run logic. I show the use of the MCD instruction with and without the update speed bit to show how the MCD command works and to illustrate how the process works. Again, using the controller tags to show the axis speeds.

I also show how to use the MCD command to get a one to one-speed command change and then I show how to use the MCD instruction to run double of the commanded speed change which is a percent of maximum. Units per second will give you a one to one ratio and a percent of maximum to get a two to 1 ratio. In this video, I show why we do not use the .DN bit of the MCD instruction to change the speed of a servo.

Also in motion servo control part 4, I will be showing how to slave drive one servo axis off of another servo axis so when one servo axis starts to run then the other servo axis runs with it and vice-versa when a stop happens. This is an operation of a MAG instruction which is a motion axis gear, I also describe the different setup types of the motion axis gear command. This again, shows both axis running via the controller tags for each axis.

Here is video 4:

Video one is only about 42 minutes, it is important to watch the whole video of each step to get the best understanding of a servo system.

I hoped you enjoyed the article as this shows the basics of servo controls even though it was somewhat long. I hope you learned a better understanding of a standard servo control setup and the instruction. I will be having much more topics regarding servo controls to break into a more in-depth look what to do in an advanced servo controls setup.

For the best servo training on the internet then try my course below:

Here is the link to that training course:

Servo Motion Training

Or visit my YouTube channel at:

Shane Welcher – Servo Controls

Again, I hope you were able to pick up some good learning and please let me know what topics that you are interested in for further articles.

Leave me a comment.

Thanks,

Shane

 

 

 

 

Servo Controls with 

RSLogix 5000 

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