"Slip adjustment" function
The "Slip adjustment" function is integrated only in MOVISAFE® CSA31A. The "Slip adjustment" function is used for the automatic adjustment of an incremental position measuring system that is prone to slip. This system is part of a safety-related setup with a second absolute position measuring system. A guided rail vehicle, driven by wheel-rail coupling (friction contact, prone to slip) and positioned using a slip-free position measuring system, is used as an example.
Position measuring will inevitably diverge because the position measurement system mounted on the driving motor (incremental) and the second absolute position measuring system that is slip-free are evaluated at the same time. The "Slip adjustment" function corrects this slip by setting the incremental value to the actual physical position at certain positions. One cam (e.g. switch lug) is required per defined adjustment position for this purpose. The hardware position switch (NC contact) is read‑in at the safe digital input F-DI of the CSA31A safety card and the "Slip adjustment – cam" function is assigned to the safe digital input F-DI in the function assignment. Only single-channel sensors are permitted.
By passing over the cam, the "Slip adjustment" function evaluates the current position value at the falling edge in conjunction with the corresponding entry in a position table. If the current position value is within the specified tolerance range to a corresponding cam position and the current speed is less than the parameterized maximum speed, the encoder system with slip is adjusted with the rising edge. For this purpose, the current position value is overwritten with the second position value.
To use the "Slip adjustment" function, the cam positions must be parameterized in the "Assist CS..." parameterization tool. You have to enter 2 position values for each switch position to be adjusted.
The encoder system must be referenced. If an edge is identified on a position that is outside of the parameterized tolerance, the slip adjustment function triggers the "Slip adjustment" fault response. If the "Slip adjustment" fault response is triggered, the "Referenced" bit is set to "0" and the encoder system must be referenced again.
