Step 3: Calculate deltas

If the input state is Normal, various deltas values are calculated based on the volume and mass flow rates multiplied by the elapsed time since last processing. If the input state is anything other than Normal, the deltas are zero.

Where:

• Δt = Elapsed time since last processed (hours)

• Qm = Mass flow rate

• Qv = Volume flow rate at flowing conditions

• Qb = Volume flow rate at base conditions

• ΔP = Orifice differential pressure reported by the differential pressure analog (inches of water)

• Pfu = Upstream flowing fluid pressure