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3 Functional safety (FS)
Safety-rated encoder
Addendum to the Operating Instructions – Synchronous Servomotors CMP40 – 112, CMPZ71 – 100
12
3 Functional safety (FS)
3.1 Safety-rated encoder
The following encoders are available as safety-rated motor option for synchronous
servomotors.
• AK0H, part number: 13356615
• AK1H, part number: 13410547
In the safety-rated design, encoders and the procedure of installation in the synchron-
ous servomotor comply with the requirements for functional safety. In this case, the
encoders are only permitted to be used in the described unit combinations. It is not
permitted to adapt them to other motors.
The safety-related use of encoders is intended to realize safety functions in regard of
speed, direction of rotation and stop. For this purpose, the encoder is coupled to the
motor shaft. The encoder system cannot trigger responses on its own initiative as a
result to encoder-internal diagnostics. This requires a higher-level safe evaluation
device that detects interferences, which could lead to a hazardous situation.
Increased demands are placed on the electrical and mechanical coupling, e.g. the
shielded connection lead stranded in pairs with correct wiring in line with EMC direct-
ives.
INFORMATION
For the safety-rated encoders AK0H and AK1H, only the Sin/Cos interface is safety-
rated. The RS485 interface (Hiperface
®
) is not safety-rated. The absolute position val-
ues, as well as other data (e.g. nameplate, diagnostics) can be referred to for general
diagnostic purposes.
3.2 Underlying standards
The safety assessment of the encoder is based on the following standards and safety
classes:
Underlying standards for safety-rated encoders
Safety class/
underlying standard
• Safety Integrity Level (SIL) according to
EN 62061:2005/IEC 61508:2011
• Performance level (PL) according to
EN ISO 13849‑1:2008
3.3 Encoder mounting
The connection between the encoder and the motor is a safety-rated frictional connec-
tion.
The mechanics and the corresponding connections can be included in the safety con-
sideration as fault exclusion according to EN ISO 13849‑1. Observe the mechanical
limits in chapter "Technical data" (→
2
24).
22491465/EN – 03/2016