Technical information

Technical Information 9
Radar Tank Gauge
Inputs and Outputs
Terminal Assignment
The 4-wire cable is connected to the screw terminals
(wire diameter 0.5…2.5 mm) in the terminal
compartment. Use 4-wire twisted pair cable with screen
for the connection. Protective circuitry against reverse
polarity, RFI, and over-voltage peaks is built into the
device.
Accessing the terminal compartment
Terminal Connections
Note! Minimum load for HART communication: 250 Ω
Note! Refer to the 4590 TSM technical information for con-
nection to the 4590 TSM.
Input Power
The 7500 Series Radar Tank Gauges operate on a DC
voltage 16-36 VDC power source.
Overvoltage Protector
The 7500 Series Radar Tank Gauge is equipped with an
internal overvoltage protector (600 Vrms surge arrester)
according to DIN EN 60079-14 or IEC 60060-1 (impulse
current test 8/20 μs, Î = 10 kA, 10 pulses). Additionally,
the instrument is protected by a galvanic insulation of
500 Vrms between the power supply and the (HART)
current ouput. Connect the metallic housing of the
7500 Series Radar Tank Gauge to the tank wall or screen
directly with an electrically conductive lead to ensure
reliable potential matching.
Installation with additional overvoltage protector
HAW262Z/HAW56xZ (see XA081F-A "Safety
instructions for electrical apparatus certified for use in
explosion-hazardous areas").
• Connect the external overvoltage protector and the
7500 Series Radar Tank Gauge to the local potential
matching system.
• Potentials shall be equalised both inside and outside
the explosion hazardous area.
• The cable connecting the overvoltage protector and
the 7500 Series Radar Tank Gauge shall not exceed
1 m in length;
• The cable shall be protected e.g. routed in an
armoured hose.
Output Signal
4…20 mA with HART protocol (e.g. for multidrop
connection to the 4590 Tank Side Monitor): this version
can be operated via the PC operating software ToF Tool.
The instrument supports both point-to-point and
multidrop operation.
Note! For measurements with mm accuracy the measured
variable must be transmitted using HART protocol to ensure
the necessary resolution.
Galvanic Isolation
• 500 V towards ground.
• 500 V between power supply and signal.
Communication Terminal
voltage
min. max.
Power supply Standard U (20 mA) = 16 V 36 V
Power supply Ex U (20 mA) = 16 V 30 V
Signal Ex U (4 mA) = 11.5 V 30 V
U (20 mA) = 11.5 V 30 V
12
3
4
12345
1
3
2
4
5
Commubox
FXA195
DXR375
HART
test sockets
(output current)
power:
24 VDC
(16…30 V)
e.g. from
NRF590
signal:
24 VDC
e.g. from
NRF590
communication
resistor
(> 250 )?
alternatively