On a new install, the tech had much difficulty in running the line without receiving Continuous Press Miss-feed Errors. We were unable to get to the root cause of the issue due to time constraints. When testing on the PC simulator we also saw an intermittent problem. We decided to review all of the feed profile calculations for accuracy and a few things were found that may or may not explain what was happening at the customer.

The calculation that determined when a triangular profile vs a trapezoidal profile could be used assumed that the press provided enough time such that the maximum velocity could be reached using the programmed acceleration.

Trapezoidal move calculations were being made using the result of the prior incorrect calculation.

The trapezoidal calculation method was also determined to be incorrect. It attempted to adjust only the acceleration. It appeared to work under the test conditions but it was mathematically unsound and did not achieve consistent results.

A new simpler, accurate, method was used. The actual move velocity can be calculated using the Maximum Velocity and a proportional relationship between the required move and the Maximum Cont Press Move. The acceleration rate can be calculated using the actual move velocity and the time under acceleration during a Maximum Cont Press Move. Using the same acceleration and constant velocity times as a Max Cont Press Move is what allows the proportional velocity and acceleration rate calculations to be mathematically sound. This achieves very consistent results.

The following changes were made to help troubleshoot Continuous Press Configuration issues.

A green line is added at the point where the last Feed Ok test is made. If the Feed OK (red line) turns ON after this line then the feed arrived in time. The relationship between the green line and the red line will show how close we are to Press Miss-Feeds and how consistent the feeds are.

One of the Feed OK lines was being hidden by a white line that shows when the press turns Off or is cleared (considered OFF). On a continuous press the cleared line was almost always coinciding with the Feed OK transition. The Feed OK transitions are more important so the cleared line was removed.

When DIP Switch 12 enables the Continuous Feed option the controller can stop the material and halt at any time during a Continuous Feed. A continuous Feed is a feed that is longer than the Max Contiuous Press Move distance while the press is still active.

If the line was halted in the middle of one of these moves it was taking three seconds to turn off the press. When investigated it was discovered that the controller was doing a tolerance test and waiting the Tolerance Timeout time of 3 seconds after the material stopped. It could not pass tolerance because the feed was terminated early. The code that turns the press ON and OFF is executed after the tolerance test Passes or Fails and this explained the delay.

This tolerance test is no longer performed on the Continuous Feed moves and the press turns off an imperceptive amount of time after the material stops.

When the "= Fault" capture option was added it stopped and saved the data capture anytime the drive was disabled. Faults cause the drive to become disabled.

An improvement has been made to also stop and save the data anytime the controller drops out of its current run mode. This allows the user to capture and save the data that proceeds any sort of error message that causes the controller to exit the run mode.