ZHCSH75A September 2017 – December 2017 ADS7142
PRODUCTION DATA.
The modes which are specifically designed for autonomous sensor monitor applications are Pre-Alert mode and Post-Alert mode. In Pre-Alert mode, the ADS7142 can be configured to monitor sensor outputs and continuously fill the internal data buffer until a threshold crossing occurs. The ADS7142 generates an ALERT signal when the sensor output falls outside of the predefined window of operation. In this particular mode, the ADS7142 stops filling the data buffer when the threshold is crossed and provides the last 16 samples (15 sample data preceding the sample at which the ALERT is generated and 1 sample data for which the ALERT is generated). Figure 117 shows the ADS7142 operation in Pre-Alert mode showing 16 data samples before the sensor output crosses the low threshold. This is useful for applications where the state of the signal before the threshold is crossed is important to capture. Using the data captured before the alert, deep data analysis can be performed to determine the state of the system before the alert. This type of data is not available with analog comparators.
In Post-Alert mode, ADS7142 can be configured to monitor sensor outputs and start filling the internal data buffer after a threshold crossing occurs. The ADS7142 generates an ALERT signal when the sensor output falls outside of the predefined window of operation. In this particular mode, the ADS7142 continues to fill the data buffer after the threshold is crossed for a total of 16 samples (1 sample data for which ALERT is generated and 15 sample data after the sample at which ALERT is generated). Figure 118 shows the ADS7142 operation in Post-Alert mode showing 16 data samples after the sensor output crosses the high threshold. This is useful for applications where the state of the signal after the threshold is crossed is important to capture. Using the data captured after the alert, deep data analysis can be performed for to determine the state of the system after the alert to detect system-level events such as saturation. This data is not available with analog comparators.