Beckhoff Releases Multi-Functional Input Module With Unique Accessories and Control Options

October 16, 2020 by Seth Price

Beckhoff recently released the ELM3702-0000 data acquisition module with EtherCAT technology.

This module has been designed for both laboratory and industrial use and features multiple input configurations and fast sampling rates.


The ELM3702-0000 Module

The ELM3702-0000 module is a 2-channel, 24-bit, multifunctional input module. This input module can be configured for over 30 types of input signals, ranging from strain, thermocouples, Resistance Temperature Detectors (RTDs), potentiometer output, and others. 

Measurements are taken using differential mode, instead of single-ended, meaning small signals, electrically noisy environments, and longer cables are acceptable. These data acquisition modules are suitable for the academic laboratory environment or the industrial and manufacturing environment. 


The ELM3702-0000 module. Image courtesy of Beckhoff


One advantage of this module is the quick sampling rate. Samples can be collected at 10 kHz, or 10000 samples per second per channel, simultaneously. 

This means short-lived events, such as a brief pressure pulse or a momentary strain can be captured and recorded by this device. The Nyquist theorem states that the sampling rate must be at least twice the frequency of an incoming signal to be accurately represented. Therefore, a 10 kHz sampling rate will accurately represent the frequency of a signal up to 5 kHz.

This is fast enough to capture many vibration and noise signatures with an accelerometer. By collecting this data, one can analyze the vibration signature and predict when a bearing is wearing out or when a pump impeller is being damaged by cavitation or a variety of other common industrial problems.


Data Collection and Flexibility

Another feature of the ELM3702-0000 is its data collection flexibility. Based on the configuration, the module can take voltage measurements from ±60 V for larger signals or as fine as ±20 mV, with multiple settings in between. It has a built-in Wheatstone Bridge circuit for detecting the change in resistance measurements, used in strain gauges, some pressure gauges, and RTDs. 

Current input ranges from ±20 mA, meaning the industrial control standard of 4-20 mA can be monitored using this module. Users can also monitor the temperature with several standard RTDs, such as the Pt100, and virtually every type of thermocouple, from the common J and K to the more expensive S and T types. The module has built-in cold-junction compensation for minimizing instrumentation error due to dissimilar metals in the thermocouple connection.

The ELM3702-0000 module. Image courtesy of Beckhoff. 


This data acquisition device can be connected to other modules using the Ethernet for Control Automation Technology (EtherCAT) protocol. Beckhoff developed EtherCAT with the industrial environment in mind. It has built-in error checking (with a checksum) and minimal variation in timing (jitter), making it ideal for high-speed data acquisition. 


Unique Accessories and Control Options

The EtherCAT allows for connection with a computer, PLC, or other control devices.  

The module can be purchased with a few optional accessories, such as the shielded hood, for limiting interfering signals. This shielding is especially essential when measuring small signals, such as voltage from a thermocouple or Wheatstone bridge. 

The ELM3702-0000 can be integrated with Matlab/Simulink or LabVIEW software, both popular in academic and research laboratories. 

Overall, the ELM3702-0000 aims to add value to any industrial or laboratory data acquisition or control loop where fast sampling is required. It can be reconfigured for a variety of sensors for changing environments and new developments in sensing technology.