Offset of the analog position differs by more than one sector
The positional information of a SINCOS rotary encoder is coded with the help of an analog sinus and an analog cosine track (a sine/cosine period equals one PPR). The angle within a stroke period is calculated as follows:
Angle = arc tan (measured sine value/measured cosine value).
The track signals are used in the main processor (DSP) to continuously calculate the position. Positional information from the track signals is also formed in a register of the CPLD (A1) within the pick-up evaluation of the drive controller. The analog positions of the two separate pick-up signal evaluations are continuously compared with each other. As the CPLD register is reset to zero at the time a rotary encoder is activated, an offset arises between the analog position (i.e. the calculated position in the DSP) and the position value in the CPLD register, which depends on the current position on activation of the rotary encoder. This offset value is calculated on initialisation of the rotary encoder and is displayed in parameter ID2345 (“Analog Offset [Ax]“).
The error is triggered if the offset changes by more than one sector, i.e. more than 90° related to a signal period. The error is fatal and leads to immediate shutoff of the drive controller. In this case the drive coasts to a standstill.
Renewed release of the drive by the controller is prevented until the cause of the error has been corrected and the error has been acknowledged.
The error can be acknowledged from the control centre after the cause of the error has been corrected.
Source And Remedy
If the error occurs repeatedly,
the rotary encoder or the pick-up lead may be defective,
the M drive may be defective
Check the pick-up lead for correct plugged connections, intact signal leads and functioning shielding.
If necessary, replace the controller cassette or the rotary encoder.