PRODUCT INFORMATION
Digital Microwave Tank Gauge
8900d Digital Radar
Tank Gauge for continuous and non-contact precision level measurement
For custody transfer and inventory control applications
Features and Benefits
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Application
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±1 mm level accuracy FMCW range measurement
DSP data extraction via dual FFT algorithm
Graphical Display Panel (with view select)
Integrated temperature probe interface ±0.1°C
Water level and density inputs
Optional integrated graphical display
Optional Tankside Remote Display
4-wire combined power and communications cabling
Compatible with NT5000 Tank Gauging System and other Host
Systems
Simple commissioning and maintenance through NT5000 diagnostic
interface
Columnated Horn
Gas tight process connection rated to 40 bar.
8900d digital radar is designed for use in custody transfer tank
gauging applications and exceeds the requirements of UK weights
and measures standards for tank gauging.
8900d Digital Radar
SYSTEM FUNCTION
Measuring Principle
8900d is an ullage-referenced tank contents level measurement device. It
measures the range (R) from a reference position inside the gauge to the liquid
surface using the FMCW method.
The product level (L) is calculated by subtracting the measured range (R) figure
from the tank empty range (E) value.
Returned
Signal Strength
R
E
L
Increasing
Range
In FMCW, or frequency modulated continuous wave, radar measurement the
emitted radar signal frequency is modulated between two values and the
difference between the transmitted signal and the return echo signal is
measured. This difference frequency is directly proportional to the distance from
the target.
In storage tanks there may be many ‘targets’ in addition to the liquid level (eg,
pipes, fittings, coils, ladders, weld seams, false echoes from tank roof) and the
difference frequency measured may consist of many component frequencies,
each frequency representing a target.
8900d uses a dual FFT algorithm together with peak tracking to ensure that the
liquid level is correctly identified and processed.
The gauge is known as a ‘digital radar’ due to
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the digital techniques employed to generate the highly accurate linear
frequency sweep within the synthesized pulse and
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the high order digital signal processing using to analyse the return
signal which and which delivers the resulting ‘picture’ of the tank and
its contents.
Product Information
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8900d Digital Radar
Tank Top Connectivity
Temperature
Probe
Pressure Tx
Water
Probe
Tankside
Display
8900d provides tank-top interfaces for
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Temperature measurement (average or spot)
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Level alarms (discrete outputs)
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Water level measurement (separate water probe)
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Density measurement (separate density probe)
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Tankside Display Unit
and with optional expansion I/O provides a gateway for control and monitoring
of tankside valves and other discrete devices
Control Room Connectivity
8900d interfaces with host systems via a two-wire field bus which may be
configured in either a star or multi-drop network.
As the gauge runs on two-wire 24Vdc it is possible to run the communications
and power signals in the same cable.
The field bus provides continuous updates of level, temperature and status data
for all connected gauges. The entire register map of each gauge is also available
for dynamic access during gauge commissioning and for diagnostic purposes.
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Product Information
8900d Digital Radar
Installation Overview
Item
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2
3
4
5
6
Qty
1
2
1
12
2
1
Description
Adaptor Plate
Slip Ring
Gasket
Bolting
Gasket
Gasket
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8900d Digital Radar
SPECIFICATION
GENERAL DESCRIPTION
High Accuracy Microwave Tank Gauge –
Non-intrusive FMCW radar level detection with auxiliary inputs
for temperature, density and water interface
APPLICATION
Custody Transfer / Inventory Management
Problematic Petrochemicals
PERFORMANCE
Level Accuracy
Level Measuring Range
Temperature Accuracy
Temperature Measuring
Range
ELECTRICAL
Electrical Safety
Power Supply
Power Consumption
Microwave Emissions
Lightning Protection
COMMUNICATION & CONTROL SYSTEMS Host communications
Alarm Outputs
Analogue Inputs
Temperature
Integral Display
Remote Display unit
PHYSICAL
Exterior Protection
Environmental Protection
Tank Operating Temperature
Working Pressure
Weight
Process Connection
± 1mm
0-40 Metres
± 0.1oC (from Spot/Multiple Averaging/Multiple
Spot Probe)
-50oC to +200oC
II 1/2G EEx d [ia] IIB T4 (tamb = -20oC to
+45oC)
Standard: 15-24Vdc
Options: 110/ 130/ 220/ 240 Vac 50/60 Hz
Less than 12 Watts
Less than 0.1m W/cm2
Full Galvanic and Optical Isolation to 5kA
Electrical Interface RS485 2-wire half duplex
Protocols Modbus RTU, MCS proprietary
4 off Digital Outputs
4-20mA Input
20 RTD inputs from Spot/Multiple
Averaging/Multiple Spot
Probe, Cu or Pt elements
Illuminated Graphics Display Panel with
selectable display
Scrolling LCD display (instrinsically safe)
Standard: Aluminium LM25
Option: Stainless Steel AISI 316
IP67/NEMA 4
-40oC to +200oC
Up to 40 bar max
25Kg
2”, 3”, 4”, 6”, 8” as required
Motherwell Control Systems
St Michaels Road
Lea Green Ind Est
St Helens
Merseyside
England WA9 4WZ
Tel : + 44 1744 815211
Fax : +44 1744 814497
sales@motherwellcs.com
www.motherwellcontrolsystems.co.uk
E&OE
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Product Information