Remote monitoring applications in fields such as oil and natural gas extraction, environmental monitoring, and fleet management often require close attention to detail. Users need to accurately record and track several variables including temperature, flow, strain, stress, vibration, and more. Therefore, when purchasing a new data logging solution, it’s crucial to understand the exact capabilities and specifications of the device you need. However, the sheer variety of data loggers and data logging systems can often make it difficult to choose the best model for your application. With this in mind, here are 10 things which customers purchasing for remote applications need to know to choose the right data logger for their project.
- What do you want to accomplish? Consider whether you need a quick fix for a specific problem or a long-term solution providing a general need with room for expansion. Details such as knowing how many and what types of inputs are required are important, along with how often readings need to be taken (determining the logger’s sampling rate) since there’s such a wide range of options available.
- Also what else needs to be taken into account is whether the data logger must be equipped with external sensors or built-in sensors, or if programmed alarms are needed. Will the logger need to perform real-time calculations on the measured data? This could be avoided by installing an RTU (Remote Telemetry Unit). Will the device need output signals? Having a clear initial idea of what requirements are needed and what features might become necessary in future are key factors in making the most suitable choice.
- The type of sensors being recorded is also critical in the decision process. Ideally, the data logger will have the versatility to accommodate the wide range of sensors you may need to connect it to. For instance, if the application calls for using thermocouples, the logger must support TC inputs. Likewise, if the application must accommodate several different inputs (including current-loops, voltages, pulses, etc.) then it will require a more flexible, powerful data logger. Will a large number of inputs be needed to adequately monitor your conditions? Are expectations are to only measure and log analog signals, or will digital signals also be recorded?
- How about ruggedized a device which can survive hazardous working conditions including dust, dirt, and accident. Depending on the application, the data logger may need to be safely encloses in a sturdy industrial or portable enclosure. Also, how often will the data logger need to be transported? Will the device need to be moved between jobs, which could jostle an unprotected unit and reduce its longevity? Will it be installed in a vehicle? These questions will help protect the data logger.
- Also determine how the logger will be powered. Will a battery-operated device for extended operation needed? Again, this depends on the logger’s location, whether it’s going to be installed inside a vehicle or in a more stationary location.
- Ensure that the data logger has a visible LCD display which will clearly show measurements in its given environment, whether in dim lighting, underground, or outdoors. This will especially help when presenting the data to clients, instructing personnel in its use, or when showing your project to others.
- No matter the budget, look for cost-effective options which give extensive features for an economical price. If future expansion is anticipated for the project, search for data loggers with a modular design so other capabilities can be added when needed.
- Most data loggers can record at a rate up to about 1Hz (once per second), although many faster recording frequencies are available. It’s important to determine the right recording rates for the application. When recording from a K-Type thermocouple, for example, the sensor/sample may take several seconds to change temperature, making a high-sample device give redundant data. Depending on the application, it may only be necessary to capture a few minutes’ worth of data or the need may be to store entire months of readings. This can be easily determined the amount of data storage required by multiplying the number of channels by the sample rate and recording duration, given in this quick formula:
Total Number of Points = Number of Channels x Sample Rate x Recording Duration.
Since model specifications vary, there may be a limit based on the total amount of internal memory, or the data logger may offer the option of using external memory such as a USB memory stick to expand the available memory. Options like these can significantly cut down costs.
9. Many data loggers are designed for a fixed installation, but other devices are intended for portable applications, such as those commonly required for environmental monitoring. How remote is the application where the data is being collected? Is the logging environment located underground? For many industrial applications, a USB memory stick serves as the fastest way to get the data, especially when the data is in an unalterable format intended for clients to view. This method also provides a quick onsite set up allowing a user to gather all the data using USB. Communication with the data logger for setup, monitoring, and downloading data can be done in many different ways, including those which continuously send the data directly to the software interface.
10. When it comes to software, look for a user-friendly interface that enables a fast configuration. Preferably the software will be included free with the data logger. Software should be accessible by both novice and veteran users.
Above all, go with the capabilities which prove the most practical for your application and analysis. If you’re looking for data trends, use the statistical capabilities offered by certain data loggers to summarize the data over an interval. If you’re looking for anomalies, use the triggering features in many data loggers to simply capture a window around the event. All of these features and more are available to ensure that the data logger chosen handles every aspect of your application.
Established in 2004, NorthTree Associates (Waconia, MN) is a North American distributor that specializes in providing design engineers, test engineers, and production engineers the best electronic test & measurement tools available.
(Revised article re-posted with permission from our valued partner CAS Dataloggers – originally published May 14, 2012)