Siemens SIRIUS 3TK2810-1 Manual page 16

Introduction
1.6 Product-specific information
Encoder
NOTICE
Use of encoders
In order to achieve the highest possible SIL/PL when using encoders, 2-channel encoders (4
tracks: A, A/, B, B/) with defined failure response (high-impedance outputs) must be used.
If such information cannot be found on the encoder manufacturer's data sheet, then the failure
response data must be requested from the encoder manufacturer.
No specific safety encoders have to be used on the 3TK2810-1 safety-related speed monitor.
If an encoder is used, the encoder's FIT (Failure in Time) value must be incorporated into the
calculation of the safety chain.
Encoders that are operated on a 3TK2810-1 safety-related speed monitor must have the
following properties:
• TTL/HTL encoders that provide two signal tracks with the respectively inverted signals.
• All sin/cos encoders that supply both the sine and the cosine tracks with the respectively
inverted signals (sin, /sin and cos, /cos).
• The phase offset of the two signals A (or sin) and B (or cos) must be 90 °, between A and /A
or B and /B it must be 180 ° in each case.
• The encoder's signals must have a high resistance in the event of failure.
The 3TK2810-1 speed monitor detects a disrupting offset of the signal track or mutual
overtaking of the signals in the case of sin/cos encoders. Detection of the fault is independent
of the set frequency. The 3TK2810-1 safety-related speed monitor assumes the safe state and
issues a fault message.
It is the responsibility of the user to check whether a specific encoder and its pin assignments
match the 3TK2810-1 safety-related speed monitor.
Actuator wiring up to PL e / Cat. 4 per ISO 13849-1, or SILCL 3 per IEC 62061
Figure 1-1
16
13 23
14 24
Q1 Q2
Dual-channel actuator wiring via two terminals
3TK2810-1 safety-related speed monitor
Equipment Manual, 05/2020, NEB926246402000/RS-AE/007