X20(c)SA4430
Data sheet V1.141 X20(c)SA4430 Translation of the original documentation
17
9 Module function
The safe analog input module is suitable for safely acquiring current signals for safety-related applications up to
PL e or SIL 3.
Danger!
Possible failure of safety function
Dangerous system behavior due to incorrect use of analog signal values
When using analog signal values, note the information listed in the data sheet regarding the function-
ality, precision and scope of the data.
The current drawn via the input terminals is converted into measurement voltages via shunts 1 and 2, smoothed by
the hardware filters (1st-order low pass / cutoff frequency 500 Hz) and digitized in the subsequent A/D converters.
The filter values configured in the software are applied during digitalization in the A/D converter.
The signals then pass through the 3 stages of digital signal processing.
The safe analog input channels (data type SAFEINT) are formed by the arithmetic mean value of the two individual
signals. At this point, also note the information about channel diagnostics.
The validity of analog signals is represented by the associated status signals. These binary status signals (data
type SAFEBOOL) must also be evaluated each time the analog signals are used. A binary status signal with the
status FALSE indicates an invalid value in the analog signal. In these situations, the analog signal is no longer
permitted to be used for safety-related assessments.
To exit an error state, a reset must be carried out. For this to be possible, a valid signal must be received at the
analog input for the duration of the I/O update time. The error can then be acknowledged by a rising edge on signal
"SafeRelease0x0y".
An optional sensor power supply is available to provide power to the sensors. If the sensor is supplied externally,
the 2-wire connection examples must be used. Current measurement protects the module's internal sensor power
supply against overload.
