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.
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.
Technical
Specifications:
Evaluation Unit
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.
Utilizable span
: 10 to 4500 PF
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.
Loss of Head indicator
Fail Safe Select
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.
Probe
Probe Head
: Cast Aluminum weather proof
Mounting Flanged or screwed as per requirement standard
Length 750 to 1500 mm Rigid, with grounding tube as reference and still-well.
Insulation Full PTFE
NB:
1) Reference probe required for non metallic tanks / weirs.
2) Grounding tube required for turbulent liquids.
3) 2-core shielded cable required for electronic insert to Evaluation unit interconnection up to 1
km. (users’ scope).
Specifications:
Evaluation Unit:
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.