A Closed Loop Die Accelerator that relies on a Hydraulic Cylinder potentially has a bi-directional tuning problem due the different surface areas on either side of the Hydraulic Piston. We have had the Hydraulic Option that adds features like Dither and Deadband for hydraulics, but we have never had directional tuning parameters for Loop Gain, Lag Compensation, and Acceleration Feed Forward.

When the Hydraulic Option is enabled, this change adds Reverse Loop Gain, Reverse Lag Compensation and Reverse Acceleration Feed Forward settings for Standard Linear Die Accelerators.

When Switching any of these values, they must be switched when the Loop is in a stable stationary state, or the Loop will generate ugly jumps in the Velocity Command signal (Analog). To provide a period when the Loop is in a stable state, there must be a pause in the Setpoint generation between direction changes. There will be a small, nearly imperceptible pause when switching directions when the reverse tuning parameters are used. This pause is incompatible with the Multi-Hit Die Accelerator option so these parameters will be unavailable in that application. A standard linear Die Accelerator will be the only application that is supported.

Intelligent Die Home Positioning is also technically incompatible with reverse tuning. However, since the die moves very slowly during the period when it is shifting for minor line speed fluctuations , I am hopeful that it won't be a problem.

Reverse Loop Gain defaults to zero. When Reverse Loop Gain is zero, the standard Loop Gain will be used in both directions.

There is no Lag integral in the reverse direction. This could conceivably be added as an improvement in the future. The customer that is waiting for these parameters is unable to use the forward integral. It doesn't make sense to delay them for an option they cannot use.

Reverse Lag Compensation defaults to zero. When Reverse Lag Compensation is zero, the standard Lag Compensation will be used in both directions, assuming Lag on Die Return is enabled.

Reverse Acceleration Feed Forward defaults to zero. When Reverse Acceleration Feed Forward is zero, the standard Acceleration Feed Forward will be used in both directions, assuming Lag on Die Return is enabled.