# Measurement data acquisition

## Measurement data acquisition: Definition, areas of application and technology

Data acquisition refers to the methods and technology by which physical values such as temperatures, pressures or vibrations are recorded by sensors and measuring devices. Determining measurement values, measuring equipment and their application as well as the associated basic terms of metrology are defined in DIN 1319. Measurement values can be communicated as both analog and digital values. Analog measuring methods generally display measured values on scales whereas digital measuring methods usually use numerical displays. It is also common to communicate measurement values as electronic analog or digital signals, especially for further processing in control, regulation or data processing systems. Delphin Technology is an expert partner for measurement applications in industrial environments.

## The measuring principle: Basis for acquiring any measurement value

Measuring requires a physical basis – the measuring principle. According to DIN 1319, the measurement principle allows measurement of a quantity other than a measurement variable (measurand) and to use its value to unambiguously determine that of the measurand.

Such a circuitous approach is necessary because human senses are incapable of recognising the majority of physical quantities.

One of the few physical quantities that can be directly measured by humans using a scale is length. For other physical quantities, for example temperatures, electrical voltage or masses, a measuring method and a measuring device are required, in accordance with the measuring principle. A measurand can then be transferred to a measurable signal and made "understandable" for humans. A temperature measurement can be used as a simple example here. The "temperature" measurand can be converted to a simple linear measurement: the higher the measured temperature, the further a pointer moves along a scale. By applying one or more measuring principles to a temperature measurand, which cannot be determined precisely by humans, the measured value "X degrees Celsius" can be obtained from being read from a scale.

## Analog and digital data acquisition

Physical quantities can be recorded both as analog and digital values. Analog measurement data acquisition means acquiring an analog measurement value by a sensor and transmitting it in analog form. The signal parameter of a certain value range is then assigned any value in the further course of measuring. High-impedance analog signals, e.g. when measuring pH values, can cause errors in signal transmission due to moisture or electromagnetic influences. Delphin Technology therefore uses galvanic isolation for analog inputs in its measuring devices to ensure undistorted analog signal transmission.

In digital data acquisition, the signals are digitally acquired and digitally transmitted during a measurement. In contrast to analog measurement, the signal parameters of a certain value range can only assume predefined values. A complete measurement value, comprising a numerical value and a unit of measurement, is therefore transmitted from the digital sensor to the measuring device.

### Advantages of analog data acquisition

• Even the slightest changes in measured variables can be monitored
• Fluctuating measurands can be detected
• Voltage states can be monitored

### Advantages of digital data acquisition

• Automatic detection of measuring range
• High precision
• Comparatively robust

## What options for measurement data acquisition do Delphin Technology products provide?

Delphin Technology measurement equipment is specially designed to meet the high demands of industry, test stands and laboratories. The wide range of requirements is reflected in the wide range of products available. Delphin Technology products can be used to perform the following measurements and more.

## Measurement data acquisition using a PC

In laboratories, service areas or on testing sites, systems are required to record measurements such as temperatures, currents and voltages quickly and easily using a PC. Expert Key devices from Delphin Technology feature universal inputs for connecting any sensors, individually adjustable measuring rates, easy connection to PCs via USB or LAN and the fastest acquisition speeds.

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## Modular measurement data acquisition

Modular measuring systems are used in applications that span a wide area. Modular measuring systems are also required for applications that require input and output extensions. Delphin's ProfiMessage D system provides fully scalable data acquisition, from a few channels up to 1,000 channels in a single system, perfectly adaptable to the specific needs of an application. ProfiMessage D's internal data storage capabilities for measurement data, extensive signal processing functions and various I/O modules make it ideal for tasks in field trials and complex industrial plants.

## Measurement data acquisition in laboratories

Key to work in laboratories is the flexibility and ease of use of measuring equipment. The LoggitoLab as well as the Expert Key device are designed for use in laboratories and at universities. The devices allow any sensors to be used, can acquire data from laboratory equipment via serial interfaces and permit connectivity to laboratory information management systems. The Expert Key device is used as a complete solution comprising hardware and user-friendly software for series experiments, laboratory automation and dosing applications.

## Mobile data acquisition

Mobile, flexible and easy-to-use measuring solutions are required in the machine and plant engineering sector, e.g. for commissioning systems anywhere in the world and for service call-outs. Delphin's mobile stand-alone devices and individually configurable measurement cases enable mobile data acquisition with high resolution. The autarchic, mobile units can process all standard analog or digital signals and provide the fastest analysis options using intuitive software.

## Transient measurement data acquisition

Long-term and continuous recording of measurement data is required in many areas of application, such as sound distribution measurement, troubleshooting and pressure pulse measurement. Delphin's Expert Transient device can acquire 8 or 16 analog channels synchronously and in parallel at up to 50 kHz sampling rate per channel. The Expert Transient technology does not use a PC, which makes the solution particularly stable and reliable in recording. Expert Transient's PROFIBUS sniffing for measurement data and system expandability up to 64 analogue inputs provides maximum reliability in the most demanding applications.

## Measurement data acquisition with galvanic isolation

Earth current loops, potential displacements and electromagnetic interference can falsify measurement readings making entire measurement series unusable. Galvanic isolation interrupts electrical conduction between two circuits or decouples two conductive objects from each other. Galvanic isolation of inputs is standard in Delphin Technology devices, making the solutions particularly suitable for applications with long cable lengths, in EMC-heavy environments or with interlinked measuring circuits.

## Measurement data acquisition for temperatures

Temperature measurements are used in almost all areas of application in measurement technology. Delphin products have been perfected for high-precision temperature measurement, whether using thermocouples or resistance sensors. In decades of practice, Delphin hardware has been adapted to meet special challenges. Without the need for additional measuring transformers, Delphin devices can measure temperatures down to +/- 0.05K using universally configurable analog inputs for any thermocouple or resistance sensor, high-precision and galvanically isolated 24-bit A/D converters and precise internal current sources for reference current supplies.

## Measurement data acquisition via fieldbus

In industrial environments, especially in mechanical and plant engineering, control, sensor and actuator systems are usually networked via fieldbuses. ProfiMessage, Expert Transient and Expert Vibro from Delphin can transfer measured values via PROFIBUS, Modbus, TCP or CAN interfaces. Bidirectional data exchange is possible, as is the transfer of control commands from the PLC to Delphin devices.

## Measurement data acquisition via GPS

Determining position via GPS signals is one of the latest additions to Delphin data loggers. An integrated GPS sensor records GPS data according to the NEMA protocol, enabling the devices to determine longitude, latitude and speed autonomously and online. GPS data is available as software channels and can be merged with any measurement data. This makes it possible to establish correlations between measurement data and position data, making the solution particularly interesting for measuring in crop trials, field testing or for diagnosing effects using machines with variable positions.

## Measurement data acquisition and remote monitoring

Measurement data acquisition with remote monitoring enables decentrally acquired measurement data to be centrally monitored and analysed online. Delphin Technology hardware and software products make it easy to perform remote monitoring, including the acquisition of measurement data.

## Acquiring process and energy data

One of today's most important needs is to optimise energy consumption. EEG regulations also stipulate that certain industrial companies must optimise their energy consumption. Delphin Technology provides energy data acquisition hardware and software solutions ranging from measurement data acquisition through to monitoring.

## Pressure pulse measurement and analysis

Liquids and gases are stored or transported in pipeline systems and tanks. Pressure spikes may occur due to unpermitted conditions. Media (liquids or gases) that are abruptly stopped release high impulse energies. Such pulse energy can inflict major damage to pipeline systems with valves and flaps. To ensure safe operation, Delphin provides solutions for both data acquisition and analysis of time-synchronous measurements.

## Combined power measurement

Delphin products such as ProfiMessage D enable power and process data to be recorded synchronously for combined power measurement.