Yaskawa Fully Closed Loop Control Control (Dual Loop, Glass Scale, External Encoder)
Calculator
Use the calculator on the server to get Yaskawa Drive parameters, and steps per settings for Mach
Yaskawa Fully Closed Loop CalculatorRev11.xlsx
Also see this folder for encoder config files, as well as some info on each encoder in the .txt files
You can find additional information here: Yaskawa Fully Closed Loop.
In tuningless mode, you likely will have to adjust the rigidity: Yaskawa Mini Manual.
As long as the safety relay is reset and you have drive power, you can test the encoder on large machines by jogging here and making sure feedback pulse counter and Fully closed feedback pulse counter go the same direction. You have to turn off drive enable from the control but leave on hardware enable.
Scale Engineering / Selection
To make sure you engineer a scale with enough resolution, use the Scale Selection tab of the "Yaskawa Fully Closed Loop Calculator" to confirm Pn20A is greater than 100. Otherwise be prepared to have to manually tune the system or that it might not work at all.
Manually Tune Servo Gains
If auto tuning doesn't work, you may have to manually tune the servos.
Turn off Tuning-less Function in the drive
Set Pn170.0 to 0 to disable the auto gain adjustment
PN100 Speed loop Gain. Lower numbers means softer
PN101 Speed Loop Integral Time Constant. Higher number means softer
PN102 Position loop Gain. Lower numbers means softer
Calculate the Moment of Inertia Ratio
Run the first step of Auto Tuning with SigmaWin to calculate the Moment of Inertia Ratio and save that to the drive. Also verify that the calculated percent is less than 400, if its greater than 400 then the motor is not sized correctly.
Troubleshooting
Shaking Motion
Check your Pn20A ratio to make sure the scale has enough resolution. Open the "Yaskawa Fully Closed Loop Calculator" to run the numbers or for a running system you can just view the parameter in the drive. Our goal is to always be above 100... but we have tuned systems with lower value. If there is backlash on the system, it will be difficult to tune with a lower value.
Tools for Troubleshooting
To track down encoder issues, you can graph the encoder counts and velocity in Mach4.
Here's an example of an encoder overflowing. This should never happen but in this case the encoder wasn't configured correctly.
To see how you are doing while tuning or just overall performance, graph Feedback speed, External encoder speed, and Torque Reference. This allows you to see how much lag there is between the motor and the external encoder... basically shows how backlash is responding.
Here is how to setup a graph inside Sigmawin:
Here is an example of an average move on a sluggish system (lots of backlash):
In this graph, you can see there's almost an 80 ms delay between the motor and the external encoder (80ms of movement with NO movement on the encoder!). This was on a B axis on a boring mill.
This is an example of an unstable tune... the gains are too high.
