# Technical Data SMU

{% columns %}
{% column %}

<p align="right"><strong>Probability of a dangerous failure per hour (PFH)</strong></p>
{% endcolumn %}

{% column %}

PFH = 51.7 \* 10<sup>-9</sup> 1/h
{% endcolumn %}
{% endcolumns %}

{% columns %}
{% column %}

<p align="right"><strong>Activation of a safety function</strong></p>
{% endcolumn %}

{% column %}

Switching on two channel to 0V. One-channel switched safety inputs lead to turn off the power stage and requires a restart of the XENAX®  servo controller.
{% endcolumn %}
{% endcolumns %}

{% columns %}
{% column %}

<p align="right"><strong>Reaction time of the safety inputs</strong></p>
{% endcolumn %}

{% column %}

< 4ms until activation of a safety function
{% endcolumn %}
{% endcolumns %}

{% columns %}
{% column %}

<p align="right"><strong>Level of safety inputs</strong></p>
{% endcolumn %}

{% column %}

\> 21.0V safety input inactive

<  2.0V safety input active

Voltage levels outside of these limits are prohibited
{% endcolumn %}
{% endcolumns %}

{% columns %}
{% column width="50%" %}

<p align="right"><strong>Hierarchy of safety functions</strong></p>

<figure><img src="/files/klZL8fFI1857sji6amPp" alt="" width="188"><figcaption></figcaption></figure>
{% endcolumn %}

{% column width="49.999999999999986%" %}

4 STO Safe Torque Off

3 SS1 Safe Stop 1

2 SS2 Safe Stop 2

1 SLS Safetly Limited Speed

Safety functions of higher levels override those at lower levels.
{% endcolumn %}
{% endcolumns %}


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