The alarm levelscan then be set to a percentage or factor above this background reference level. A digital display (#) displays the percentage of dust in relation to the alarm level, having a span of 0-200% of the chosen alarm level setting. The 4-20mA output is scaled 0-200% of alarm level 1, allowing the operator to determine how the dust level is compared to a pre-determined limit or warning level.

The two alarm levels can be used to set both warning and emission limit levels to assist operators in potential failures from their arrestment plant.

Alarm delay and data averaging are user selectable. The DS30 series complies with the UK EPA requirement for indicative monitoring andEuropean requirements for filter performance monitoring. .