VFD Autotuning

2rlp

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Join Date
Sep 2006
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Mumbai
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I have used a lot of VFDs ranging from ABs 1336Impact, Yaskawa's G5 and currently A1000 series on hoists and other lifting applications. These were always in either Closed Loop Vector or Sensorless Vector Modes



I have always first performed a Rotary Tuning with the motor decoupled from the load. After this was done, I would couple the load, and perform an Inertia Tuning with at least 60% load.


Now when I read the Yaskawa manual, it says "perform Inertia Tuning without any load"


Have I being doing it wrong all this time?


Kindly advise
 
The full quote for the A1000 regarding Inertia tuning is:
"Perform both [inertia] tuning methods with the machine connected to the motor, but without the load applied."

Example
Machine = conveyor
Load = boxes of chocolate

Machine = robot arm
Load = car door

It is a poorly worded sentence.
 
I have used Yaskawa drives for many years
it is not possible to do a rotation auto tune on a hoist you have the limits of the hoist to consider.
I always do a non rotation auto tune on them never had a problem.
if I were doing a hoisting application I would chose Electromotive by Magnetek

http://www.magnetekmh.com/

they are Yaskawa drives with custom firmware just for cranes
they have a lot of safety features added just for hoisting one of the main ones is proof of torque on all motions.
 
Wouldn't any differences between the Drive Output/Motor/Machine model and the actual Drive Output/Motor/Machine/Load be attributed to Load Torque?
Or can you explain further what I may be misunderstanding?
 
The autotune is more for the motor electrical characteristics, rather than the motion/speed control. The motion autotuning comes after you get the motor tuned properly.

For example (from Control Techniques):

Parameter: 05.012 Auto-tune
Short description: Defines the auto-tune test to be performed
Mode RFC‑S
Minimum 0 Maximum 5
Default 0


Value Text
0 None
1 Stationary
2 Rotating
3 Inertia 1
4 Inertia 2
5 Full Stationary



The following describes how an auto-tune test can be initiated and normal operation can be resumed after the test for RFC-S mode:

An auto-tune test cannot be initiated if the drive is tripped or the drive inverter is active, i.e. Drive Healthy (10.001) = 0 or Drive Active (10.002) = 1. The inverter can be made inactive by ensuring that the Final drive enable is inactive, or the Final drive run is inactive and Hold Zero Speed (06.008) = 0.

An auto-tune test is initiated by setting Auto-tune (05.012) to a non-zero value and making the Final drive enable and the Final drive run active.
All tests that move the motor will move the motor in the forward direction if Reverse Select (01.012) = 0 or the reverse direction if Reverse Select (01.012) = 1.
If the auto-tune sequence is completed successfully the Final drive enable is set to the inactive state and Auto-tune (05.012) is set to zero. The Final drive enable can only be set to the active state again by removing the enable and re-applying it. The enable can be removed by setting Drive Enable (06.015) = 0, or by setting bit 0 of the Control Word (06.042) to 0 provided Control Word Enable (06.043) = 1, or by making Hardware Enable (06.029) = 0.
If a trip occurs during the auto-tune sequence the drive will go into the trip state and Auto-tune (05.012) is set to zero. As in 4 above the enable must be removed and re-applied before the drive can be restarted after the trip has been reset. However, care should be taken because if the auto-tune was not completed the drive parameters that should have been measured and set up will still have their original values.
If the Final drive enable is made active, the Final drive run is inactive and Hold Zero Speed (06.008) = 1 the drive would normally be in the Stop state (i.e. the inverter is active, but the frequency or speed reference is 0).
The following describes the effects of the auto-tune test on the drive parameters for RFC-S mode:

All auto-tune tests rely on the motor being stationary when the test is initiated to give accurate results.
If Select Motor 2 Parameters (11.045) = 0 then the parameters associated with motor map 1 are updated as a result of the test, and if Select Motor 2 Parameters (11.045) = 1 the parameters associated with motor map 2 are updated.
When each stage of the test is completed, the results are written to the appropriate parameters and these parameters saved in the drive non-volatile memory. If Parameter Cloning (11.042) is set to 3 or 4 the parameters are also written to a non-volatile media card fitted in the drive.
The table below shows the parameters required for motor control indicating which should be set by the user and which can be measured with an auto-tune test.

Parameter Required for Measured in test
Rated Current (05.007) Basic control User set-up
Rated Speed (05.008) Basic control User set-up
Rated Voltage (05.009) Basic control User set-up
Number Of Motor Poles (05.011) Basic control User set-up

Measured / Test
Stator Resistance (05.017) Basic control 1, 2, 5
Ld (05.024) Basic control 1, 2, 5
Maximum Deadtime Compensation (05.059) Basic control 1, 2, 5
Current At Maximum Deadtime Compensation (05.060) Basic control 1, 2, 5
Current Controller Kp Gain (04.013) Basic control 1, 2, 5
Current Controller Ki Gain (04.014) Basic control 1, 2, 5
No-load Lq (05.072) 1, 2, 5
Motor And Load Inertia (03.018) Speed controller set-up and torque feed-forwards 3, 4
Inertia Times 1000 (04.033) Speed controller set-up and torque feed-forwards 3, 4
Position Feedback Phase Angle (03.025) Basic control with position feedback 1, 2, 5
 
it seams that you are confusing no rotation with no load
no rotation means the motor is connected but it dose not rotate during the test
as described above the auto tune tunes the drive to the motor
I would really like to see somebody do a rotation auto tune on a hoist
at some point in the process you will runout of cable and stall the motor or worse snap the cable, the tune will not complete
 
I would really like to see somebody do a rotation auto tune on a hoist
at some point in the process you will runout of cable and stall the motor or worse snap the cable, the tune will not complete
The auto tune procedure should provide limits so the end of the cable is not reached. There isn't a need to move that far. Why do you think auto tuning a hoist is that difficult?
 
When i tune fanuc drives I do a rotational tune with the motor coupled to the moving apparatus, whether it be a table, or screw or slide. (I guess that can be considered a "load")

But i do not tune it with a "load" on the table or slide or whatever may be sitting on top of it. (Fixture etc.)

I can also set tuning parameters/limits for rotation.
Travel 300mm, then return.
 
Last edited:
I have been involved in many projects where rotational auto was not possible
Cranes are just one type
the no rotation auto tune works just fine
some projects you can't run the motor in reverse but you still need to tune it
In the Yaskawa drives the inputs are disabled in auto tune in fact they can be run any or all of the inputs disabled
as for the load the motor would be a load of sorts not a very large load but a load
but as I said for a crane system I prefer to use Electromotive drives they are designed for crane duty not just a label on the drive
 
I have been involved in many projects where rotational auto was not possible
Cranes are just one type
You repeat yourself. You didn't state why auto tuning is not possible.



the no rotation auto tune works just fine
some projects you can't run the motor in reverse but you still need to tune it
Unless the load is different going each direction, it is only necessary to go in one direction.


Actually, auto tuning isn't really that automatic.
 
what I said was rotational auto tuning was not possible
there many reasons that you can't do the rotational auto tune
travel distance is the most common but I have also had motor that could not be run in reverse for some reason ( auto tune will run the motor at 80% seed in both directions)
when I you can't do the rotational auto tune then the nonrotational auto tune can be done it will give you good results
 
Another instance where rotational autotune is not possible with the machine connected is when there are upper or lower speed limits. During rotational autotune, the timing procedure will run its course from zero to base frequency of the motor. In some applications that can be dangerous. I too believe that the autotune procedure is just to set up the motor parameters needed for the vector algorithms. Load tuning is only done AFTER the drive is already tuned to the motor.

I only do rotational auto tuning when I need high precision out of the speed or torque performance. Even in those cases I always start with a static autotune and see if I get what I’m after and if not, I then do a rotational autotune. Hoists are one place I always to a rotational however. I cut my teeth on flux vector drives with torque proving used on hoists at Boeing (Electromotive and later, A-B), where the idea of letting a 777 aircraft drop an inch when you released the brakes was not just unacceptable, it was potentially deadly.
 

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