Endress+Hauser LPGmass, Руководство пользователя

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LPGmass
4 Hauser
Function and system design
Measuring principle The measuring principle is based on the controlled generation of Coriolis forces. These forces are
always present in a system when both translational and rotational movements are superimposed.
F
c
= 2 · ∆m (ν · ω)
F
c
= Coriolis force
∆m = moving mass
ω = rotational velocity
ν = radial velocity in rotating or oscillating system
The amplitude of the Coriolis force depends on the moving mass ∆m, its velocity ν in the system and
thus on the mass flow. Instead of a constant rotational velocity ω, the sensor uses oscillation.
Density measurement
The measuring tube is continuously excited at its resonance frequency. A change in the mass and
thus the density of the oscillating system (comprising measuring tube and fluid) results in a
corresponding, automatic adjustment in the oscillation frequency. Resonance frequency is thus a
function of medium density. The microprocessor utilizes this relationship to obtain a density signal.
Temperature measurement
The temperature of the measuring tube is determined in order to calculate the compensation factor
due to temperature effects. This signal corresponds to the process temperature and is also available
as an output signal.
Measuring system The device consists of a transmitter and a sensor. If a device with Modbus RS485 intrinsically safe is
ordered, the Safety Barrier Promass 100 is part of the scope of supply and must be implemented to
operate the device.
The device is available as a compact version:
The transmitter and sensor form a mechanical unit.
Transmitter
Device versions and materials:
Compact, aluminum coated:
Aluminum, AlSi10Mg, coated
Configuration:
Via operating tools (e.g. FieldCare, DeviceCare)
A0016693
Sensor
LPGmass • Simultaneous measurement of flow, density and temperature (multi-
variable)
• Nominal diameter range: DN 8 to 50 (³⁄₈ to 2")
• Materials:
– Sensor: stainless steel, 1.4301 (304)
– Measuring tubes: stainless steel, 1.4539 (904L)
– Process connections: stainless steel, 1.4404 (316/316L)
• Limiting medium pressure range: max. 100 bar (1 450 psi)
A0029466