Data acquisition is the process of acquiring real-world information from sensors and converting the sample data into numeric values that can be manipulated by a computer. By using remote data acquisition modules, users can monitor and control their applications on central computers based on the information received from remote modules, and implement control logic operations such as automatically turning on a fan based on temperature or turning on a pump based on tank level. Data can be transferred from data loggers or other measurement sensors to a host PC, allowing users access to real-time status and trends of the application at a remote site.
Remote data acquisition modules are usually compact, lightweight, and easy to use. They support RTD, thermistor, thermocouple, voltage, current, strain gauge, counter, frequency, relay, digital input, and digital output. They are easy to install and maintain, offering great reliability and flexibility for control and monitoring projects. There is also reduced risk of electrical faults and hazardous conditions compared with other devices.
Data acquisition technology provides tremendous benefits to a wide variety of industries, such as energy monitoring, remote data logging, manufacturing, water treatment, earthquake monitoring, hydrologic applications, and more. Applications can range from monitoring pressure levels in gas pipelines to controlling hundreds of vending machines at different remote sites. The growing demand for renewable energy and the need for industrial automation to increase efficiency are driving the growth of the global data acquisition (DAQ) market.
Here is a typical data acquisition application diagram. It shows a computer program running on a PC connected to an Ethernet switch, which is connected to an Ethernet-based thermocouple input and digital output module. The program reads temperature data and triggers a fan to turn on or off based on the temperature detected by the thermocouple.
Depending on the communication protocols they support, easy-to-use remote data acquisition systems can be categorized into three types: Modbus RTU-based DAQ equipment, Modbus TCP-based data acquisition devices, and ZigBee wireless data acquisition products.
Modbus is a serial-based communication protocol and one of the most widely used protocols in industrial automation. Originally published by Modicon (now Schneider Electric) in 1979 for its Programmable Logic Controllers, Modbus allows communication between up to 255 devices connected to the same Modbus RTU network—for example, a system that measures temperature and humidity and communicates the results to a computer.
Modbus is widely used because it is openly published, royalty-free, and easy to deploy and maintain. It is often used to connect a supervisory computer with a remote terminal unit (RTU) in SCADA systems.
Modbus RTU is derived from a master-slave architecture and communicates over RS-232 and RS-485 using two copper wires. It is the most common form of Modbus in industrial applications.
The ICP DAS USA M-7000 series consists of Modbus RTU-based remote I/O modules. They are available in a wide variety of analog and digital configurations, offering full digital and analog data acquisition capability. For example, the M-7017 is an 8-channel voltage and current analog input module that supports ±150 mV, ±500 mV, ±1 V, ±5 V, ±10 V, and ±20 mA. It also comes with free EZ Data Logger software for PC-based data logging and control.
The M-7017 is commonly used in renewable energy applications to monitor current and voltage generated by solar panels and wind turbines. When connected to SCADA software on a PC, users can view real-time current and voltage data from remote power stations.
Modbus TCP is a simple, vendor-neutral communication protocol that supports Ethernet communication. Ethernet has been increasingly adopted in industrial applications due to its ease of integration, lower cost, and high bandwidth. Modbus TCP-based data acquisition solutions offer greater interoperability and faster processing for businesses.
The ICP DAS USA ET-7200 series Modbus TCP-based dual Ethernet port I/O modules include two Ethernet ports for daisy-chain networking and can work easily with standard Ethernet switches. Daisy-chaining simplifies cabling and reduces the cost of switches and wiring.
As remote web-based Ethernet I/O modules, the ET-7200 series also feature a built-in web server that allows users to configure devices and monitor systems directly from a web browser. Users can create dynamic web pages for I/O monitoring and control without programming or HTML skills. These modules also include free EZ Data Logger software.
Real-life example:
The ICP DAS ET-7000 series has been used to build an emergency warning system in a tunnel. The system controls cameras and receives signals from smoke sensors and transmitters. ET-7000 modules connect to these devices and send digital outputs to LED displays that warn drivers about obstructions. This helps keep the roadway safe and traffic flowing smoothly.
With the rise of the Internet of Things (IoT), industrial wireless communication has opened up new possibilities for flexible and efficient automation. Wireless devices offer significant benefits for remote control, maintenance, and monitoring.
ZigBee is a specification based on the IEEE 802.15.4 standard for wireless personal area networks (WPANs). It allows users to easily add intelligent features that enhance efficiency, safety, security, reliability, and convenience. ZigBee can help reduce energy consumption, improve automation, and support health or environmental monitoring.
ZigBee operates in the ISM radio bands and provides a low-cost, self-organizing mesh network suitable for industrial control. Applications range from building automation to industrial monitoring, embedded sensing, smoke detection, remote control, and more.
ZigBee devices can work with data acquisition products for I/O Pairing, where the input of one ZigBee module wirelessly triggers the output of another.
Example:
The ZT-2052-IOP digital input module can trigger the outputs of the ZT-2042 module using built-in I/O pairing. No external controller is required. The ZT-2052-IOP continuously sends input status updates to the ZT-2042 to ensure synchronized digital outputs. Configuration is simple with DIP and rotary switches.
The ZT-2052-IOP constantly sends status updates of the digital input channels to the remote ZT-2042 to ensure that the digital output channels are synchronized. It comes with external DIP and rotary switches for easy configuration. ZigBee Alliance based modules with I/O pairing can be used to synchronize digital signals in any environment where wiring is inconvenient.
ZigBee wireless converters and data acquisition modules are also used in factory automation systems for monitoring and control. For example, a ZT-2570 host repeater connected to a laptop running Indusoft SCADA software can communicate wirelessly with multiple ZT-2571 slave converters connected to devices such as VPD-133 touch screen PLCs, ZT-2060 digital I/O modules, and ZT-2053 input modules. All data is collected on the SCADA PC, where users can view system status, generate reports, log data, review alarms, and analyze trends.
