Experimental Physics and
Industrial Control System

"J. Lewis Muir" <[email protected]> · Tue, 25 Sep 2012 15:01:24 -0500

On 9/25/12 1:45 PM, Fong, Nia W. wrote:
> Hi,
> 
> We just setup our motors to use a readback link URIP, getting motor position from an external LVDT device and are running into a problem when the motor is moved to one of its soft limits.
> 
> We notice that when a motor is moved to its soft limit, it is possible for the motor to end up at a position slightly outside of its soft limit (how far out depends on how high we set the retry deadband RDBD).  As a result, the motor can no longer be moved until the soft limit it is violating is manually widened outside of the RBV value.  According to the motor record documentation, HLM uses the VAL, but it looks like it is instead using the RBV field.  Both fields would seem valid depending on the application.  
> 
> Has anyone else run into this problem using URIP and the HLM and DLM?  How was it resolved?

Hi, Nia.

I've run into the same problem, but not using URIP.  My scenario
is like yours: I can't move the motor because it is beyond one
of the soft limits.  My workaround is to temporarily extend or
disable the soft limits, move the motor back to a position
within the original soft limits, and then restore the soft
limits.  If there's a better way, I'm interested in hearing it.

Lewis

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System