Switches Indicators & Gauges

Data Loggers

Data loggers are devices that record the measurements of sensors, whether they are internal (as in combination loggers and sensors) or external. They can be designed for general purpose applications then programmed to specific parameters, or be very specific devices designed for only one application with no changeable parameters. Electronic data loggers replaced chart recorders, and have the benefit of being able to automatically detect data 24 hours a day. This means that during the period specified to be monitored, a comprehensive and accurate record of the conditions being recorded is available.

Data loggers can interface with a remote computer that has software to analyse the data, or can be self-contained with a local interface with keypad and screen. They are designed to be extremely durable and reliable, as the loggers are often left in harsh and remote conditions for long periods of time. Any failure to record data could potentially compromise the record. Data loggers can be used in a whole range of applications from environmental conditions, weather station recording, road traffic counting, process monitoring and tank levels.

WATERLOG® H-350-XL and H-350

The Model H-350-XL is a microprocessor controlled pressure sensor and data logger designed for remote operation, while the Model H-350 is designed for use in the laboratory. They can be interfaced with data loggers, chart recorders, GOES transmitters, remote displays and telemetry systems.

The combined loggers and sensors replace mercury manometers, are compatible with SDI-12 and RS-232 data loggers, are seared in a corrosion-resistant nonconductive enclosure, and operate in temperatures between -40° and 60° C. They also come with built-in temperature compensation and auto-zero functions, and data logging capability using a non volatile internal storage.

These WATERLOG® combined loggers and sensors are available from Semrad’s environmental water products division, as well as data collection platforms, sensors, gas bubbler systems, communication products and rain gauges.

Data Loggers and Sensors

Water management sensors measure a range of variables such as water levels and precipitation amounts. They can use different technologies to determine measurements, whether by magnetostrictive, hydrostatic, air bubbler, vibration, rotating paddle, capacitance, optical, ultrasonic or microwave/radar. Sensors vary according to whether the substance being measured is a liquid, semi-liquid or solid. They can measure continuously or at specific points, such as at pre-determined points (such as when levels drop below or rise above certain points). 

The type of sensor used depends on the type of substance (i.e. liquid, semi-liquid, or solid), agitation or vibration, density, whether it must detect measurements in a vacuum or under pressure, the temperature, the type of container, the chemical composition of the substance, noise and so on.

Data loggers are electronic devices that record the data collected by the sensor. They are generally small, portable, battery powered and have a microprocessor and internal memory. Some data loggers interface with a remote computer and users then use software to view and analyse the data, while others have a local interface device (e.g. keypad and screen) so it can be used as a stand-alone device.

Combination Loggers and Sensors

Data loggers can receive data from external instruments and sensors, or can come built in with an internal sensor. Those with internal sensors are combination loggers and sensors. Semrad Pty Ltd offers a range of  WaterLOG® combination loggers and sensors:

• H-350-XL : a microprocessor controlled pressure sensor / data logger designed for remote operation. Interfaces with data loggers, chart recorders, GOES transmitters, remote displays and telemetry systems. Replacement for mercury manometres.
• H-350 : Pressure measurement system / manometer replacement including keypad display data logger using PCMCIA flash card and GOES radio options.
• DH-21 : H-310 sensor combined with logger and software.
• H-510 : Self-contained shaft encoder with SDI-12 data recorder.

WaterLOG® Communication Products

Semrad Pty Ltd produces a range of communication products to be used with sensors and data recorders. These include the WaterLOG® H-424-MS Spread Spectrum SDI-12 Radio Bridge,  the WaterLOG® H-260 e-Modem and  the WaterLOG® H-222-SE GOES Radio.

The Spread Spectrum SDI-12 Radio Bridge provides transparent, SDI-12 compliant communication between data recorders in one or more remote sites, using modern direct sequence spread spectrum telemetry radios. Each remote site can have multiple SDI-12 sensors. The radio link is easy to use, its frequency range is between 902.5 to 927.5 MHz, and can operate in environments of -40 to +60º C and 0 – 100% humidity. It is enclosed in fibreglass and is warranted against defects for one year from date of shipment.

The GOES Radio links up with  the H-350, H-350XL, H-510, H-500, and H-500XL allowing any of the sensor readings to be transmitted over the GOES Radio system. It has a menu driven setup interface, allows for self-timed and random transmissions and has extensive built-in software. The Configuration Query allows examination of set-up parameters and the time of day query retrieves GPS time from the transmitter for time management of other terminal devices or sensors.

The e-Modem

Finally, the e-Modem is used with XL Series Data Loggers to send collected data from the field via Internet Email. It interfaces with  H-350XL, H-500XL and H-510XL data loggers, and transmissions can be based on programmable intervals and/or alarm conditions. The e-Modem works with both land-line or mobile phones, email data can be sent up to three different email addresses using carbon copy (CC) feature, and that data arrives embedded in an email that can be processes using a simple application program. So  special equipment is needed in the central office. Its internal power manager also turns off the modem and mobile phone when not in use.