Safety Functions Of The Fail-Safe Evaluation Device; Mandatory Safety Checks / Measures - Pilz PSEN enc sincos/HTL Operating Manual

Basic safety information

2.5 Safety functions of the fail-safe evaluation device

The evaluation device, to which the measuring system is connected, must perform the
following safety checks.
With regard to "Single fault safety" and "Ideal error detection" please see IFA directive
"GS-IFA-M21".
To enable the correct measures to be taken in the case of error, the following
applies:
● Safe state – passive, only for measuring system – PSEN enc sincos
In passive safe state the measuring system does not output any valid
sinusoidal output signals to the downstream fail-safe evaluation device. The
evaluation device detects the error through evaluation of the magnitude SIN(x)
COS(x)
evaluated as unsafe. The downstream fail-safe evaluation device has an ideal
error detection.
● Safe state – active, only for measuring system – PSEN enc HTL
In active safe state the signal outputs are switched to high impedance. The
evaluation device detects the error via an implemented cable breakage detection.

2.5.1 Mandatory safety checks / measures

Measures for commissioning, changes
Check that the desired automation task is executed as
required.
Check by the evaluation device
Check of incremental data according to the present
automation task and safety function.
Two-channel monitoring of incremental outputs for cable
breakage.
Only for PSEN enc sincos
Evaluation of the condition SIN(x)
of checks / revolution corresponds to the number of
periods/revolution.
For the safety functions SDI, SS1, SS2, SOS, SSR, SSM a
magnitude monitoring with DC = 90 % is required.
For the SLS safety function a two-channel evaluation of the
frequency from (SIN/COS) with a DC of 90 % is required.
Only for PSEN enc HTL
A cable break detection is required for the evaluation of the
square pulse signals.
In the safe state, the output drivers are high impedance.
Only for PSEN enc HTL
Evaluation of the incremental data in differential mode and
verification with respect to antivalence, quadrature and
against phase equivalence between channels A and B
Operating Manual PSEN enc sincos/HTL
1005022-EN-01
2
= 1. If the result is outside the tolerance range, the incremental data are
2 2
+ COS(x) = 1. The number
2
+
Error reaction
evaluation device
STOP
Error reaction
evaluation device
STOP
For high impedance
-> STOP
If outside tolerance
-> STOP
If a cable break is
detected
-> STOP
If outside tolerance
-> STOP
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