The Right Data Logger: Fast data collection and retrieval in remote applications
Remote monitoring applications in fields like oil & gas extraction, environmental monitoring and fleet management often require 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 capabilities and specifications of the device.
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, the applications specialists at CAS DataLoggers present 10 things customers purchasing for remote applications need to know.
1. The Goal
According to Pete Martin, sales manager for CAS DataLoggers, “To begin searching for the right product, always keep in mind your starting point — 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 range of options open to you. Often users believe they need to record multiple channels of data at hundreds of Hz, not realizing that this will soon exceed the logger’s available memory and require more frequent downloads.”
2. Necessary Features
Take into account 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? A clear initial idea of what requirements are needed and what features might become necessary in future are key factors in making the best 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 range of sensors connected to it. For instance, if a user is planning to use thermocouples, the logger must support TC inputs. Likewise, if the application must accommodate several different inputs (including current-loops, voltages, pulses, etc.), a more flexible, powerful data logger may be required. Are you going to need a large number of inputs to adequately monitor your conditions? Are you expecting to only measure and log analog signals, or will you also need to record digital signals?
Consider a ruggedized device that can survive hazardous working conditions that include dust, dirt and hits; and depending on the application, one may need to safely enclose the logger in a sturdy enclosure. Also decide how often you need to transport the data logger. 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?
5. Power Source
Determine how the logger will be powered. Will you need a battery-operated device for extended operation? 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 the data logger has a visible LCD display that clearly shows measurements in its given environment, whether in dim lighting, underground or outdoors. This will help when presenting the data to clients, instructing personnel in its use or when showing a project to others.
No matter the budget, look for cost-effective options that give extensive features for an economical price. When anticipating future expansions, search for data loggers with a modular design so you can simply add other capabilities when needed.
Most data loggers can record at a rate up to about 1 Hz (once per second), although many faster recording frequencies are available. When speaking with a representative, it’s important to determine the right recording rates for your 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 you redundant data. Depending on the application, it may only be necessary to capture a few minutes’ worth of data or you may need 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.
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 to expand the available memory. Options like these can significantly cut costs.
Many data loggers are designed for fixed installation, but other devices are intended for portable applications, such as those commonly required for environmental monitoring. How remote is the office from where you’re collecting the data? Is the logging environment located underground? For many industrial applications, a USB memory stick serves as the fastest way to get your data, especially when the data is in unalterable format intended for clients to view. This method also lets users quickly get set up onsite and then 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 that continuously send the data directly to the software interface.
10. Software Features
Look for a user-friendly interface that enables fast configuration. Preferably, the software will be included free with the data logger. Martin adds, “Above all, go with the capabilities which prove the most practical for your application and analysis. If you’re looking for data trends, we recommend that you 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.”
This is an edited article provided by CAS DataLoggers. For more information, visit www.dataloggerinc.com.