Permitted encoders for MOVISAFE® CSA31A

The limit for overspeed detection has a quantization error for sin/cos encoders, which has the following magnitude (relating to the encoder shaft):

Error = 3000/pulses per revolution in min-1

The maximum operating speed must remain below the set value by the quantization factor.

The maximum angular error of the position value formed by the sin/cos encoder evaluation, relating to the motor shaft, results as follows:

  • 2160° × scaling_factor_denominator / scaling_factor_numerator

Parameters involved:

  • Scaling_factor_numerator
    • 8381.2 (encoder 1)
    • 8382.2 (encoder 2)
  • Scaling_factor_denominator
    • 8381.3 (encoder 1)
    • 8382.3 (encoder 2)

To increase the robustness of the incremental signal evaluation, the fault tolerance can be increased via the following parameter:

  • 8708.24 (encoder 1)
  • 8713.24 (encoder 2)

Fault tolerance sin/cos evaluation

The maximum number of successive faulty diagnostic cycles (500 μs) that should not yet lead to a fault response is set.

A fault response occurs in the following cases:

  • The set number of consecutive faulty diagnostic cycles is exceeded.
  • The ratio of faulty to fault-free diagnostic cycles over a longer period is ≥ 1/5.

Information

Increments can be lost when fault tolerance is enabled. This means the calculated position value could be incorrect. This must be detected via a second encoder channel when calculating the position value.

If a safety-rated encoder is evaluated as encoder 1 and the safety functions of the application depend exclusively on this encoder, then the fault tolerance for encoder 1 must be deactivated or set to the value "0".

The following safety encoders are permitted for use with the MOVISAFE® CSA31A safety option:

  • CDV75/CDH75 from TR electronic
  • FBPS617i from Leuze electronics

For further information on the safety encoders, refer to the corresponding documentation.