Type of data loggers and how do they work? — Encardio Rite

Data loggers are simply the devices that are interfaced with several other instruments to log data in real-time. While data recorders are used in various fields, their application in the geotechnical field is of utter importance.

Large construction sites or even civil engineering structures require continuous monitoring to maintain its health. A variety of monitoring instruments are installed at these places to record parameters such as humidity, pressure, deformity etc.

Data loggers are used for logging data from these sensors for an assigned duration, at predefined intervals, without any physical/human intervention.

Data recorders are of different types and, here, we will be discussing all of them along with their applications.

What is a data logger?

A data logger is usually compact, battery-powered and, carries a digital processor. Data loggers are interfaced with geotechnical sensors to log data from them automatically.

Once programmed, commissioned and activated, the data logger can be left unattended to measure and record data from sensors. It allows for regular structural health monitoring for minimising risk.

How is a data logger used?

Data loggers are connected to the sensors through cables. A single data logger can be interfaced with multiple sensors depending upon the availability of the channels.

After programming, these data recorders are left unattended to record data from the sensors and store it in its internal non-volatile memory. The device can log multiple parameters from the sensors along with current time, date, and battery voltage.

The data stored in the memory of data loggers is transmittable through telemetry or using a laptop/PC.

| Read More: Data Loggers: What is it, Types, Applications & How it Works? |

What is the data logger used for?

Data loggers have a wide range of applications, especially in the geotechnical field. They are used for the following purposes:

1. Large construction sites require the installation of sensors such as piezometers, strain gauges, tilt meters, extensometers, etc. These sensors are used to monitor and measure several parameters affecting the structure.Data loggers are interfaced with these sensors to record data and display it at any remote location along with specified units, date, time, and battery voltage.
2. Data recorders are extensively used to monitor groundwater level as well as, rainfall to keep a check on the natural resources.
3. They are used along with the weather stations to monitor several environmental factors.
4. Unattended nuclear power plant monitoring to avoid fatal accidents such as chemical leakage.
5. Comprehensive tunnel monitoring for the long-term safety of the tunnel, to study the behaviour of the tunnel over the time, especially with respect to the rheological behaviour of the rock mass and obvious changes in the fault zones, walled sections, inflow, etc.
6. Monitoring deformation of land and surrounding areas during deep excavations. Excavation in soft ground induces ground movement which imposes a threat to nearby sensitive structures in the zone of influence. Hence, deep excavation risk assessment and foundation crack monitoring are crucial at all the levels.

Data logger types

Bluetooth data loggers

Bluetooth data recorder is a simple wireless data logger. It measures, records, and transmits data wirelessly to computers/laptops within a specified range say, 30 metres. These data loggers work on Bluetooth connectivity.

USB data loggers

USB data loggers record and store the data in their internal memory. The data recorded can be retrieved on a PC or laptop using the USB cable interface. The same USB is used to charge up the data logger.

Web-Based data loggers

The web-based data loggers allows for remote data retrieval using Internet, Wi-Fi, or GPRS. Encardio-Rite deals with web-based data loggers. The Encardio’s range of data recorders include:

Model ESDL-30 Data logger for SDI-12 Interface Sensors

The Encardio-Rite’s Model ESDL-30 multi-channel data logger is designed to record data from sensors with SDI-12 interface. Any sensor with an SDI-12 interface can be connected to ESDL-30 e.g. based on vibrating wire, resistance strain gauge or MEMS technology etc.

ESDL-30 is a robust data logger that finds its application in a variety of fields to provide accurate and reliable data. It features a wide operating temperature range, dependable stand-alone operation, low power consumption, compatibility with many telecommunication options, and flexibility to support a variety of measurement as well as control applications. It is of durable construction and very suitable for unattended applications.

ESDL-30 data logger is connectable to a large number of sensors with SDI-12 interface. The data logger is fully compatible with all measurement commands signal as per SDI-12 standard. It can be programmed to take readings from 5 seconds to 168 hours in linear mode.

However, the number of measurements taken per day should be kept minimum to prevent power drain from the batteries.

The SDI-12 serial digital interface requires a three conductor cable to connect the sensors to the data logger. The advantage of the instrument is that only a single 3-conductor cable is required to interconnect all the sensors and the data logger to a serial bus.

SDI-12 is a multi-drop interface that can communicate with multi-parameter sensors. Multi-parameter means that a single sensor may return more than one measurement, like displacement and temperature from vibrating..(Read More)