Oversampling (for SM 531 AI 8XU/I HS)

The use of the oversampling function requires an isochronous configuration.
For analog input modules, the preset transmit clock is divided into up to 16 time-equidistant subcycles. The module reads in a measured value in each subcycle and saves it. The read in measured values of a data cycle are copied to the interface module (IM) of the ET 200MP in the next transmit clock and are available to the processing CPU one transmit clock later.
A major advantage of Oversampling is that no faster CPU-Cycle is required for recording the high temporal resolution measurements.

Scaling of the measured values (for SM 531 AI 8XU/I HF)

With scaling of the measured values, the value corresponding to the technological quantity of the process can be assigned to the physical measured values of the module (current or voltage). This saves time and memory during program processing in the CPU, as the analog input module converts the physical value directly and makes it available to the user program as 32-bit floating point value (REAL).

Measuring range adjustment (for SM 531 AI 8XU/R/RTD/DC HF)

The measuring range adjustment to the used sensor enables you to increase the resolution for a configurable section of the measuring range in S7 format. Sensors frequently do not use the entire nominal range of a module but only return voltage values in a partial range. By configuring the sensor limits in the TIA Portal, the original measuring range is expanded. The resolution of the measured values is more detailed.

Calibration at RUN (for SM 531 AI 8XU/I HF and SM 531 AI 8 XU/R/RTD/TC HF)

Repeated calibration may be particularly useful for plants in which sensors measure or process relatively small voltages or currents. Recalibration compensates for any effects on the measurement result caused by cables, temperature or sensor and can be executed in RUN of the CPU. Thereby, the latest values are acquired and saved retentively on the module.

Scalable temperature measurement range (for SM 531 AI 8 XU/R/RTD/TC HF)

To keep the process temperature at a constant operating point, the module must provide a relatively high resolution. Therefore, the operating point of the process gets defined as "measuring range mean". By limiting the measuring range to a smaller area, the 16-bit resolution of the module can be applied to this range which permits a significantly higher resolution of the measurement and therefore accurate calculations.