B&R X20cSC2212 Manual page 2

X20(c)SC2212
1.1 Function
Safe digital inputs
The module is equipped with safe digital input channels. It can be flexibly used for a wide range of tasks involving
the reading of digital signals in safety-related applications up to PL e or SIL 3.
The module is equipped with filters that are individually configurable for switch-on and switch-off behavior. Switch-
on filters are used to filter out signal disturbances. Switch-off filters are used to smooth testing gaps in external
signal sources – i.e. OSSD signals – so that unintended cutoffs can be avoided.
The input signals of signal pairs (channels 1 and 2, 3 and 4, etc.) are monitored in the module for simultaneity.
The maximum permitted discrepancy of inputs of a signal pair is configurable. Here, the signals of dual-channel
evaluation directly represent the safe signal of a 2-channel sensor, such as from an E-stop button or safety light
curtain.
The module provides pulse signals for diagnosing the sensor line. By default, each pulse signal provides a unique
pulse pattern derived from the module's serial number and pulse channel number. This allows any pulse signals
to be combined in one signal cable and still cover any cross fault combinations in the cable. The pulse check can
also be disabled to connect electronic sensors with separate line monitoring (OSSD signals).
Safe digital outputs
The module is equipped with safe digital output channels. It can be flexibly used for controlling actuators in safe-
ty-related applications up to PL e or SIL 3.
The outputs are designed using semiconductor technology so that the safety-related characteristics do not depend
on the number of operating cycles. In order to handle all situations involving actuators, there are basically 2 dif-
ferent types of outputs: the high-side - low-side variant (type A) and the high-side - high-side variant (type B).
Type A outputs have safety-related advantages since the actuator can be cut off in its connection cable in all error
scenarios. Type A outputs are limited to actuators without ground potential (e.g. relays, valves). For actuators with
ground potential (e.g. enable inputs on frequency inverters), type B outputs are required. It is important to observe
the special notices for the cabling in this case.
Safe digital output channels provide protection against automatic restart when network errors occur. Function
blocks needed to fulfill additional requirements regarding protection against automatic restart are available in
SafeDESIGNER. The outputs can also be controlled by the standard application. The combination of safety-related
control and standard control is arranged such that the execution of a cutoff request always has top priority. For
diagnostic purposes, the outputs are designed to be read back.
Depending on the product, the safe digital output channels are equipped with current measurement for detecting
open circuits. This function can also be used to monitor muting lamps, for example.
The testing of the semiconductors that is necessary from a safety point of view results in what are known as
OSSD low phases in many products. The effect of this is that when an output is active (high state), a switch-off
situation (low state) occurs for a very brief amount of time. The test can be cut off if this behavior leads to problems
in the application. Observe the associated safety-related notices!
openSAFETY
This module uses the protective mechanisms of openSAFETY when transferring data to the various bus systems.
Because the data is encapsulated in the openSAFETY container in a fail-safe manner, the components on the
network that are involved in the transfer do not require any additional safety-related features. At this point, only
the safety-related characteristic values specified for openSAFETY in the technical data are to be consulted. The
data in the openSAFETY container undergoes safety-related processing only when received by the remote sta-
tion; for this reason, only this component is involved from a safety point of view. Read access to the data in the
openSAFETY container for applications without safety-related characteristics is permitted at any point in the net-
work without affecting the safety-related characteristics of openSAFETY.
2 Data sheet V1.141 X20(c)SC2212 Translation of the original documentation