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 LOH |
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Loss of Head indicator
Sapcon LOH (loss of head indicator) is a perfect
solution of measuring differential level in open
channels and is widely used in water treatment
plants and filter stations. The LOH series
instruments are RISC Processor based capacitance
type Continuous Level Indicators with built in
three point switching. The system not only
serves as a level indicator for conductive/ non
conductive liquids, slurries and powdered or
fine grained solids, but also offers switching
functions for alarm annunciation and/or control
application at the set point levels through the
built in three point electronic level limit
switch. The set points are independent of each
other and are continuously configurable over the
entire range.
Salient Features:
Latest RISC core microcontroller technology.
Measured level is displayed continuously from
-50% to 150%.
Multipurpose 5 digit seven segment LED display
for best resolution and better viewing from
distance.
Two wire pulse coded digital communication from
sensor to evaluation unit.
Supports as much as 1 KM distance between sensor
and evaluation unit with shielded two core
cables.
Galvanically isolated true two wire 4-20mA
proportional to 0% and 100% level is available
for remote indication purpose.
Two wire implementation solves the malfunction
problems that occurs with various PLC 4-20 input
interfaces and thus better suits for higher end
automation.
4-20mA loop can handle 700 Ohm loop resistance
with internal isolated supply.
Three independent potential free relays
providing flexibility of selecting three
independent switch points. |
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Principle of
Operation:
The loop resistance can be 1K Ohm for
External DC Supply of 24 Volts. In an
application, the measuring electrode
(sense probe) and the container wall
(ground or reference probe) form a
capacitor. The amount of capacitance of
this capacitor is governed by the
dielectric constant of the material
between the two electrodes (sense probe
& metallic container wall or reference
probe or ground). The value of this
capacitor is dependent on the level of
material, since the dielectric of the
material is effective only to the level
to which the material is filled.
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Specifications: |
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Evaluation Unit: |
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Housing: Cast
Aluminum, Weather Proof,
Stoving Enamel Painted.
Suitable for back panel
/ wall mounting.
Cable Entries: 3
Numbers of / BSP/NPT/ 1”
Double Compression.
Operating Ambient
Temperature: 20 C to
+60 C
Power Supply:
Universal Mains 90 to
265 VAC, 50/60Hz and
24VDC (@ 3 Watt)
Sensor to Evaluation
Unit Cable: 2-Core;
resistance per core not
to exceed 30 Ohms. Use
of shielded twisted pair
cables is recommended
for long runs of cable.
Cable lengths of 1000
meters are thus
supported with grounded
cable shields.
Zero% Range: 30pf
to 250pf
100% Range: 10pf
to 4500pf (Difference
from Zero %)
Outputs: Current
4 to 20mA. 3 Potential
Free relays with One set
of Potential Free Change
Over Contact per Relay.
Contact Ratings:
6 Amp @ 230VAC 50/60 Hz
for non-inductive loads.
Indication
Continuous: -50% to
150% digitally on 1 ”
Seven Segment Display
Switching: 5 mm
Red LEDs’ for Alarm
Indication.
Switching Hysterisis:
1% in Single Point
Switching, 1 to 98%
selectable in Pump
Control.
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Loss
of Head indicator |
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Fail Safe
Select: |
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Set Point
Select:
Field Selectable
through
interactive
relay
configuration
menu.
Weight:
2.3 Kg Approx.N
Electronic
Insert - LDC117,
LCDM 111:
Housing
Plastic, potted
with epoxy
resin.
Power Supply
16VDC @ 5mA
derived from
Sensor
Communication
Interface
of Evaluation
Unit.
Measuring
Frequency:
250Khz to 20Khz.
Reverse
Frequency
Measurement.
Operating
Ambient
Temperature:
20 C to +60 C
Sensitivity:
10 counts per pF
Output:
Digitally
Encoded Current
(5mA-8mA) Pulse. |
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