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Pinball_NL
·Posted in ctrlX DRIVE

Motor holding Brake delay time - Preventing a load to drop due to gravity after Drive enabling

Where can I compensate the Motor Brake delay time.What I want is that the drive is enabled and on power before the brake is released.

I have a vertical movement with a big mass. When switching on (enabling) the drive I do not want the mass to drop, not even as small movement. I like to have it steady to get a smooth behaviour.  What I see changing the delay times is that the drive ready bit can be shifted. Its also explained in the manual.

 

When I add 100 ms in the Delay time the Drive Ready Status bit is indeed delayed. 

Where can I found the function to prevent the load to drop.

 

Best reply by Pinball_NL

I found it and its more easy as I expected.

Its called "weight counterbalance" You can fill in the load which the axis need to hold the load against gravity. You can find this parameter in Axis Control - Velocity control loop.

If you switch on the drive this torque will be applied before the brake loosen. This result the load to be on position without a drop when you enable the drive.  I made some scope measurements to make it more clear.

 

 

In normal operation the brake is spring release. You see the torque building up (green) and the position drop a little bit (blue)

When using "weight counterbalance" het on 15% you can see that the drive delivers 15% before the brake is released resulting iin smooth drive enable.

Now I found also an Exaple in the "How To's"

https://developer.community.boschrexroth.com/t5/Store-and-How-to/bg-p/dcdev_community-dev-blog/label-name/rex_c_How-to

 

 

 

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GRAVITY
HOLDINGBRAKE
MOTORBRAKE
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