SCN 3575 and SCN 4426 provide history and context for this change.

With the "Lag on Die Return" set to NO there have been disturbances in the command signal (Analog) when switching the Lag ON and OFF.

The command signal is made up of proportional, integral, Lag and Feed Forward components. If any of those components are suddenly removed or added, they will cause a disturbance (Jump) in the signal. When the Lag is turned ON or OFF during the Die Cycle, this is what happens. These disturbances are especially bad if they result in a jump in the opposite direction than the signal is already trending.

The solution is to switch the Lag ON and OFF when the Lag and Feed Forward components are as close to zero as possible and when any necessary jump will be in the same direction as the signal is already trending.

The motion profile (Set-point) code knows when it wants the Lag to switch ON and OFF. The Loop code knows when it is safest to do the switch. The Loop code will now delay the switch until the best time to do so.

When switching the Lag ON, the Loop will wait until the Filtered Set-point velocity is at or above zero.

When switching the Lag OFF the Loop will wait until the sum of the Acceleration Feed Forward and the Lag are less than 0.5% of Maximum Analog. This point in time happens during the deceleration of the die before it comes to a stop. The Set-point code now requests the switch at the start of the deceleration ramp.