Varec 7532, Installation And Operation Manual

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7532 Technical data
10 Technical data
10.1 Technical data at a glance
Application
Application
The 7500 RTG is used for highly accurate level measurement in
storage tanks and can be applied in custody transfer applications. It
meets the relevant requirements according to OIML R85 and API 3.1B.
• The 7532 RTG with planar antenna is specifically and only suited for
stilling well applications with ranges up to 38 m (124 ft).
Function and system design
Measuring principle
The 7500 RTG is a "downward-looking" measuring system, operating
based on the time-of-flight method. It measures the distance from
the reference point (process connection) to the product surface. Radar
impulses are emitted by an antenna, reflected off the product surface
and received again by the radar system.
Equipment architecture
The 7500 RTG can be used for measurement in a stilling well as well
as in free space. The different instrument versions are applied as
follows:
• The 7532 RTG with planar antenna is the preferred device in stilling
wells
≥
150 mm.
• The instruments are equipped with a passive 4…20 mA output with
HART protocol.
Input
Measured variable
The measured variable is the distance between a reference point
(mounting flange) and a reflective surface (e.g. medium surface). The
measured value and all parameters are displayed using either metrical
SI-units or US/UK-units (inch, ft, …).
The level is calculated based on the tank height entered.
The level can be converted into other units (volume, mass) by means
of a linearization.
In order to compensate for non-linear effects like movement of the
tank roof, an additional correction table (diptable) can be entered.
Measuring range
See page 15
Output
Output signal
4…20 mA with HART protocol:
this version can be operated via the PC operating software ToF Tool
and Commuwin II. The instrument supports both point-to-point and
multidrop operation.
Signal on alarm
Error information can be accessed via the following interfaces:
• Local display:
– Error symbol (see page 35)
– Plain text display
– LED’s: red LED continuously on = alarm, red LED flashes = warn-
ing
• Current output
• Digital interface
Galvanic isolation
500 V towards ground.
500 V between power supply and signal