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

[Pinball_NL]

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.

[Pinball_NL · Accepted solution]

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...

[macmotor]

Just some general comments...

You mentioned "...have a vertical movement with a big mass...". Please note that the motor holding brake is not specifically designed for holding an external heavy mass in a vertical axis. In addition to the simple software feature it is probably recommend to review the mechanic design, considerung the safety of operation and man & machine with a real "weight counterbalance" or similar.
See also notes in MS2N manual, chap. 4.11ff (or respective other motor manual)

[Pinball_NL]

Its just for enabling the axis. Normally the axis stays enabled. The holding brake will only be in charge when the machine is in Ab. Beside that there is an external construction preventing the load to fall in case of an unforseen accident. We are aware of that.

And beside that there is the brake check functionality to check the brake holding capacity.