KROHNE MFC 010 C Converter - Manual (Page 77)

MFC010 Interface Manual 75
8.3 Fixed and Referred Density Operation
In addition to t he di rectly m easured D ensity, t he MFC010 pr ovides t he us er with t wo f urther m odes of
Density determination. These can be s elected by setting the appropriate Density Mode value in Holding
register no. 1019 (see section 7.5 on page 49). N B. T he system will always use the actual measured
density in the determination of the mass flow reading, regardless of the Density Mode setting.
The Fixed Density is used when direct density measurement is not required, to calculate the Volume and
other density related measurement values. It can also be used to test Density related features such as
the Internal Process control Mechanism (see section 8.8 on page 78). When the Density Mode is set to
“Fixed” the value of the density is determined by the contents of the Fixed density register, accessed as
Holding register no. 3057/ 3058 (see section 7.5 on page 49). This value i s s caled ac cording t o t he
setting of the Density units, accessible as Holding Register no. 1021 (see section 7.5 on page 49).
In Referred Density mode, the MFC010 will extrapolate the measured density to a reference temperature
based on a defined slope relationship. The reference temperature is set in Holding register no.
3055/3056 and is scaled to the Temperature units, which ar e s et i n H olding r egister N o. 1025 . T he
reference s lope i s def ined i n H olding r egister 3059/ 3060 and i s s caled by D ensity U nits/Temperature
Units, e.g. g/cm 3 /°C.
For example, given a density of 1.233 g/cm 3 is measured by the sensor at a process temperature of
37.8°C, if the density is referred back to 20°C using a slope of 0.025 g/cm 3 /°C then the displayed density
will be ( 37.8 – 20 ) x 0.025 + 1.233 = 1.678 g/cm 3 . i.e. a measured Density of 1.233 g/cm 3 at 37.8°C is
equated to a density of 1.678 g/cm 3 at 20°C.
Product Type = 3 ?
YES Set the Density Value
(Holding Reg. 3093)
Continue Two Point
Calibration
(Set Output Reg. 1013)
YES Error During Density
Calibration (See notes)
Store Calibration
(Set Output Register 1001)
Density Calibration
Status = 1 ?
(Input Reg 1007)
NO
NO