Ratio function block alarm detection

Block alarm detection is based on the PV and SP values. You can configure the following alarm limits to compare to the PV value for alarm detection:

• High (HI_LIM)

• High high (HI_HI_LIM)

• Low (LO_LIM)

• Low low (LO_LO_LIM)

You can configure the following alarm limits to compare to the difference between the SP and PV values for deviation alarm detection:

• Deviation high (DV_HI_LIM) — The deviation of PV is above SP.

• Deviation low (DV_LO_LIM) — The deviation of PV is below SP.

IN must be connected to provide PV calculation and in order for the alarm limits to have meaning.

This block supports conditional alarming. Enabling conditional alarming makes additional parameters available for this block.