Users’ Manual
ESM-12S Digital seepage monitoring system
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The sensor has a vent tube running from inside the sensor to the outside atmosphere ensuring that sensor
reading is unaffected by change in barometric pressure. The end of the vent tube terminates into a moisture
trap assembly (described below) thus preventing any moisture from migrating into the vent tube.
The seepage sensors are available with digital SDI-12 and Modbus output. When used with SDI-12 output,
maximum distance of datalogger from the sensor can be up to 200 m. When used with Modbus output,
maximum distance of datalogger from the sensor can be 1.2 km. The bus cable is connected to the
datalogger either directly, or through junction box depending on the site conditions.
2.4 Moisture trap assembly and Junction box
The digital seepage sensor is vented to atmosphere to ensure that air pressure both inside and outside the
capsule are same so that any change in atmospheric pressure does not affect the reading of the sensor.
When air pressure (barometric pressure) changes, the fluctuations are transmitted to the sensor through
air vent tube. This results in cancelling out the effect of barometric pressure on the sensor.
The vent tube is connected to a moisture trap (with desiccant unit and hydrophobic filter), so that only dry
air can enters the sensor vent line. Desiccant and hydrophobic filter ensure that the air inside the moisture
trap is dry. Moisture content in air in the sensor vent line can, in course of time, coalesce to form water
droplets and can damage the inside of the transducer.
The desiccant capsules contains blue colour desiccant inside them. Desiccant needs changing when it
becomes pink.
The moisture trap is fixed on a wall mounting plate with the help of two clamps provided on mounting plate.
The wall mounting plate also has a junction box fixed on it. The leads from the three core cable are
terminated in the terminated box, from where a three core or six core cable can be routed to the datalogger.
NOTE:
Choice of cable depends on the distance between junction box and datalogger. Preferably,
the datalogger should be mounted next to the mounting plate, if the location has satisfactory
network (GSM/GPRS) signal.
The wall mounting plate can be fixed vertically on any vertical surface like a wall using four Hilti expandable
fasteners HPS-1 5/5x25 or equivalent.
Figure 2-2 Mounting plate with moisture trap and junction box
2.5 Model ESDL-30 Datalogger
Model ESM-12S/1 seepage/water level sensor is connected to Encardio-rite model ESDL-30 datalogger
for remote online monitoring. ESDL-30 datalogger is a compact datalogger that can be mounted easily
near the sensor or in a control room in close vicinity.
