Session: 05-01-02: Condition Monitoring, Metrology & Instrumentation

Paper Number: 166368

EtherCAT-Based Data Acquisition Solution for Instrumentation and Control 

Data acquisition systems are a key component to any experimental setup. They communicate with sensors and actuators on digital, analogue, industrial communication buses such as CAN and RS 485, with reasonable sampling rate, to collect data during experiments, and provide some graphical user interface for visual feedback. There are well-established market leaders and newer entries/approaches in this area. While expanding our research work with our industrial partners, providing training to students beyond their experiences with microcontrollers, balancing budget, and maintaining flexibility and upgradable hardware, we used EtherCAT based data acquisition hardware as alternative for several projects with reasonable success.

A typical setup requires an industrial PC with EtherCAT. It gives upgradability by installing additional modules or cards without being limited by the number of slots in the chassis or carrier board.  It allows distributed I/O because it takes advantage of TCP/IP. The structural text programming is familiar to students with MATLAB, Python, and Arduino experience. In this paper we described four cases involving EtherCAT-based data acquisition solutions.

1)      A Master's thesis investigating an electric machine dynamometer with a 60kWhr battery pack and an axial flux machine simulating an electric vehicle. This dynamometer has three major components: the battery pack (voltage and current), on the dyno are the drive (vehicle) and load motor, their respective motor drives (CAN), torque sensor (analog), and the coolant loop (flow rate and temperature). The instrumentations on all three components are network over EtherCAT allowing the main computer to control and collect data.

2)      A NASA small-scale rotorcraft test stand for vertical take-off and landing (VTOL) aircraft research. The stand uses a RFT80-6A02 400N 6-axis load cell which communicates over EtherCAT. The servos and electric speed controller (ESC) are all controlled using PWM signals. The data are collected by the main computer.

3)      Two Senior Design projects exploring motion control solutions with sensor-driven closed-loop feedback. A lemon harvesting machine and a PLA recycler which use motion control solution and analog input for temperature feedback. The main computer also recorded all the sensor readings including motor torque while running a control loop.

4)      An off-road vehicle platform for studying vehicular stability and dynamics. The instrumentation on the vehicle records multiple measurements including the chassis response and suspension travel on each wheel. The data collected will be used to implement active suspension.

However, the approach is also limited to the fact that the hardware is intended for industrial control. Within the acquisition rate (Gs/s) and the cycle time (2ms or less), repeatability and sensitivity (millivolt), and without the need to perform specific measurement methods such as electrochemical impedance spectroscopy (EIS) which typically scan from millihertz to kilohertz, this data acquisition approach has many advantages. The examples also illustrate these trade-offs.

Presenting Author: Hong-Yue Tang California State University Sacramento

Presenting Author Biography: Assistant Professor at the California State University Sacramento specializing in Sustainable Energy, Advanced Manufacturing, and Robotics.

Authors:

Hong-Yue Tang California State University Sacramento
Rustin Vogt Calfornia State University Sacramento
Matthew Nichols California State University Sacramento
Carson Sutton California State University, Sacramento
Garrett Hernandez California State University, Sacramento