The ADS1291, ADS1292, and ADS1292R provide two modes for determining whether the RLD is correctly connected:
The following sections provide details of the two modes of operation.
RLD Lead-Off Detection During Normal Operation
During normal operation, the ADS1291, ADS1292, and ADS1292R RLD lead-off at power-up function cannot be used because it is necessary to power off the RLD amplifier.
RLD Lead-Off Detection At Power-Up
This feature is included in the ADS1291, ADS1292, and ADS1292R for use in determining whether the right leg electrode is suitably connected. At power-up, the ADS1291, ADS1292, and ADS1292R provides a procedure to determine the RLD electrode connection status using a current sink, as shown in Figure 39. The reference level of the comparator is set to determine the acceptable RLD impedance threshold.
NOTE:The RP value must be selected in order to be below the maximum allowable current flow into a patient (in accordance with the relevant specification the latest revision of IEC 60601).
When the RLD amplifier is powered on, the current source has no function. Only the comparator can be used to sense the voltage at the output of the RLD amplifier. The comparator thresholds are set by the same LOFF[7:5] bits used to set the thresholds for other negative inputs.