1. 10.005(A) DWLR, PRESSURE TYPE (GW)
Approval Date: 23.12.2011 Version: 3
The DWLR unit complete with accessories to measure water level and temperature
data at specified intervals and downloading data from DWLR site to uploading the
same to office desktop should work in an integrated manner.
Sl.
no
Feature Tender Specifications
1.0 PRESSURE SENSOR
Sensor Type Vented Gauge Pressure Sensor
Measuring Range The full scale measuring range and installation
depth will be specified by the Implementing
Agency depending upon their local
requirements
Overall Accuracy 0.1% Full Scale or better.
Temperature Coefficient <0.01% Full scale/degree centigrade for water
temperatures between 10 degrees centigrade
and 40 degrees centigrade
Reproducibility 0.05% Full scale or better
Long Term Stability 0.1% Full scale or better and should ensure
long term stability without any field calibration
requirements.
Burst pressure >3 times Full scale.
Overload pressure 2 times Full scale without effect on calibration
Over voltage protection
on supply & sensor wires
Required.
2.0 DATA LOGGER
Resolution of
measurement
1 mm or better.
Equipment Specification: DWLR, PRESSURE TYPE(GW) Version 2 10.005(A)-1/5

2. Measuring interval
& measuring modes
Should be programmed to store data from 1
minute one reading to 24 hours one reading
Option A
Linear sampling mode
Option B
Linear sampling mode, user
defined/logarithmic mode and
event measuring modes .
Settling up Time < 30 minutes after submersion.
Recording capacity Non-Volatile flash data storage of more than
200000 data points (at least).
Memory type Non-Volatile Memory
Power supply Should be equipped with lithium or alkaline
battery pack, giving at least 2 years operation. Batteries must
be replaceable in the field or in local offices of the Implementing
Agency or supplier. Replacement batteries must be freely
available in India.
Communication Interface The logger must be capable of connection to a
computer via USB 2.0, and supply should
include the necessary interface cables.
The logger must be capable of future connection
to a telemetry system
Operating temp Up to 60°C
Operating humidity Up to 100 %
Built in clock Accurate to ± 1 minutes per month
Displayed time resolution 1 second
Over-voltage protection Should include lightening, over voltage and surge
protection
3.0 Enclosure for data
logger
Data logger should be concealed into a single
tubular enclosure which is waterproof and
corrosion proof.
Dimensions Outer diameter : < 50 mm, length <500 mm.
Equipment Specification: DWLR, PRESSURE TYPE(GW) Version 2 10.005(A)-2/5

3. Material Titanium, Stainless Steel or other corrosion resistant material
Installation
The data logger should be provided with an
suspension bracket allowing secure installation
within the piezometers’ headworks, including
appropriate cable mounting to allow the sensor
to be adjusted to the required depth, in a stable
and reproducible manner.
Ambient conditions Up to 60°C and 100% humidity
Cable
The cable shall have following features.
Strength members for good longitudinal stability
of cable.
Incorporated PTFE or equivalent vent tube for
barometric air pressure compensation of the
vented gauge pressure sensors.
A moisture blocking system based on a
hydrophobic filter and desiccator, to prevent
condensation of water in the vent tube and in the
sensor. The desiccant shall be replaceable.
The desiccant capacity should be adequate for at
least 6 months of unattended operations under
Indian environmental conditions. For each
instrument, two desiccant replacements must be
included.
The cable connection to the logger may be fixed
or quick connect.
4.0 Data Retrieval System
(DRS)
Laptop Laptop PC of latest configuration capable of download and
storage of DWLR data in the field.
Battery life Laptop should have a minimum of 5 hours
battery life under normal field usage, and should
be provided with an option for recharging from a
12 volt vehicle power supply in the field.
Connectivity USB 2.0 for connection to data logger
WiFi
Entry /Display/Readability The unit should have a colour LCD screen/display
optimised for readability in bright daylight in field conditions.
Software
Windows 7 OS
Software for logger control, download and
display of data in tabular and graphical
presentation form.
Equipment Specification: DWLR, PRESSURE TYPE(GW) Version 2 10.005(A)-3/5

4. S data export in ASCII format..
Carry case A dedicated carry case for the DRS must be provided.
Equipment Specification: DWLR, PRESSURE TYPE(GW) Version 2 10.005(A)-4/5