Overrange and underrange detection is provided on each channel input obtained through the 4 - 20 mA signal and the FIELD_VAL_PCT and HART_FIELD_VAL parameters. The detection point is specified in percent of scale through the I/O channel properties OVERRANGE_PCT and UNDERRANGE_PCT parameters. When the channel signal exceeds the overrange or underrange values, the status of the analog input block PV parameter is set to high- or low-limited, respectively. If you set these limits to 131% and -25% on a channel, the overrange and underrange detection is disabled.
For CHARMs whose functionality is configured as 4 - 20 mA CHARM, overrange and underrange detection is provided on the FIELD_VAL_PCT and HART_FIELD_VAL parameters. If you set the limits to -25% and 131.25% overrange and underrange detection is disabled.
For CHARMs whose functionality is configured as 0 - 20 mA CHARM, overrange and underrange detection is provided on the FIELD_VAL_PCT parameter. If you set the limits to 0% and 125% overrange and underrange detection is disabled.