Yokogawa DM8C/VD6 Liquid Density Analyzer - Manual (Page 11)

< 1. GENERAL >
1-1
IM 12T03A01-02E
1. GENERAL
Density is one of the fundamental physical quantities required when the property or composition of
a liquid sample is being determined in industrial processes. Especially, density measurement of a
sample liquid is indispensable in many industries such as electric manufactures, chemical industries,
oil refi neries and food-related applications.
The Model DM8 Vibration Type Density Meter is a higher reliable meter full of operation and
maintenance functions. The meter consists of a detector and a converter. The detector has a vibrator
and an RTD (resistance temperature detector), and outputs detected density signal (frequency) and
temperature signal (voltage) to the converter. The converter is equipped with a microprocessor to
convert the frequency signals from the detector into density values and display them. It also calculates
the density at the reference temperature according to these signals and digitally displays them.
Moreover, the converter outputs digital transmission signals besides analog transmission signals and
is further provided with a variety of functions such as one-touch calibration, selfdiagnosis.
1.1 Standard Specifi cations
1.1.1 General Specifi cations
Measurement object: Liquid density
Measurement principle: Vibration density measurement
Measurement range:
Density: 0.5 to 2.0 g/cm 3
Temperature: –10 to 100 °C
Distance between Detector and Converter: Up to 2 km
Power supply: 90 to 132 V AC or 180 to 264 V AC, 50/60 Hz
Power consumption: 20 VA
Characteristics
(overall characteristics after combing the detector and the converter)
Repeatability: 5
x10 –4 g/cm 3 (for digital output)
1 % of span (for analog output)
Linearity: ±0.5 % of span (when span is 0.2 g/cm 3 or less)
±1 % of span (when span is more than 0.2 g/cm 3 )
Temperature characteristics: ±0.5 % of span/±10 °C (Compensating error for changes in the
measuring liquid temperature and detector temperature)
Flow characteristics: ±0.1 % of span in the range of 0 to 5 l/min
Pressure characteristics: ±0.0005 g/cm 3 /±98 kPa change
Viscosity error: ±0.1 % of span in the range of 0 to 1500 cP