i750 with absolute encoder and position reconstruction: After replacing the device, the machine must be re-referenced (fixed from V01.04.00)
Removed from:
Servo-Inverter i750 FW: from V01.04.00
Behavior of the new version: Disabling the position reconstruction function via parameter 0x2DE0:28 now works completely on the i750.
Description of behavior: After replacing the inverter owithout further action, the position reconstruction running within the base firmware calculates an incorrect actual position.
This applies even if the referencing status incorrectly signals "Reference known" after switching back on.
The machine must always be referenced again to ensure that the actual position has the correct reference to the machine under all circumstances.
Background: For the position reconstruction, certain position values must be stored in the non-volatile memory of the device in the inverter (retain memory). After the device has been replaced the retain data stored in the old device is no longer available. DThe position reconstruction therefore inevitably calculates a different actual position using the retain data from the new device . See also FAQ: (202400433) (post still under construction)
Under what conditions does the behavior occur?
Replacement of the i750 servo inverter and
use of an absolute encoder and
the position reconstruction function is activated (default).
Affected products: Servo Inverter i750 FW
Short-term measures / Evaluation /:
Possibility a): After replacing the device, execute the device command 0x2822 = 40 (motor encoder) or 0x2822 = 41 (load encoder) once. This deletes the associated stored retain data and only the encoder value read out is used to reconstruct the position. The device command can be executed manually or automatically via the controller, e.g. after detecting the device.For example, after detecting the device replacement based on a changed serial number of the inverter.
Option b): Disable position reconstruction in the device. Restriction: up to and including FW version V01.03.00 , deactivating the position reconstruction function in the device via parameter 0x2DE0:28 bit00 bdoes not work as expected on i750 devices. The fix is available from FW version V01.04.00.
Reference run: If it is ensured that the display range of the absolute encoder is not left in the application, then a procedure according to a) is sufficient to be able to replace the device without a new reference run.
