Baumuller BM5-O-SAF-002, Operation Manual, Page: 87 / 182

Safety Functions
Operation Manual Safety Module for b maXX 5000 BM5-O-SAF-002/3
Document no.: 5.11016.03
87
of 180
10
10.15 Tolerance for the limit values of the safety functions
Due to the used encoder type and of the adapted measuring method thereon in the SAF
module for the calculation of the position and the consequential derived quantities, such
as speed, must be considered with regard to the system tolerances.
The most important characteristics of the encoder type SINCOS are the pulses per
revolution. The higher the PPR count the more precise is the evaluation of positioning and
speed.
The measuring of the position of the SINCOS is made in the SAF module by a four-
quadrant counter. Thereby the following tolerances apply:
m
Based on positioning:

± Standardized number of increments per revolution (65536) / 4 / Encoder PPR count
m
Based on speed:

± Standardized number of increments per revolution (65536) per ms / 8 / Encoder PPR
count
An example of a position-based function SOS:
The user sets a "Standstill tolerance"-limit value of 1000 increments for SOS in
ProSafePara. The used SINCOS encoder to the axis has a PPR count of 1024.
For the above mentioned formula a deviation of 16 increments to the bottom and to the
top of the limit value (65536/4/1024 = 16) must be taken into account.
With the setting of 1000 increments a switch-off can be made by a noncompliance of
a limit at 984 increments or alternatively after 1016 increments.
Example of a speed-based function SLS:
The user sets "maximum speed positive rotational direction" for SLS of a limit value of
1000 Inc/ms. The used SINCOS encoder at the axis has a PPR count of 1024.
For the above mentioned formula a deviation of 8 lnc/ms to the bottom and to the top
of the limit value (65536 Inc/ ms/8/1024 = 8) must be taken into account.
With the setting of 1000 Inc/ms a switch-off can be made by a noncompliance of a limit
at 992 Inc/ms or alternatively after 1008 Inc/ms.
At the resolver encoder type the position in the unit circle from the demodulated sine and
cosine signals as well as the speed (derived from this) are calculated by an arctan
calculation the position in the unit circle. The following tolerances result from this:
Positioning-based:
± 6 ‰ of the standardized number of increment per revolution (65536) =
± 393 increments.
Speed-based:
± 3 ‰ of the standardized number of increments per revolution (65536) per ms =
± 197 Inc/ms