Design of MODBUS based monitoring system for Variable Frequency Drive

Multi-protocol developments in embedded systems have given freedom to the user to choose from among a wide range of protocol standards for communication in industrial data acquisition systems. Industrial data acquisition systems provide the tractability to meet the specific needs of the application and to easily link to a personal computer via LAN, USB or Wi-Fi. They also offer the ability to interface to common industrial communication protocols like CAN or MODBUS. Different protocols perform better in different applications. The system described in the paper contains a data acquisition control system for Variable Frequency Drive (VFD) with online interaction. The monitoring system for VFD would look for deteriorating conditions within the VFD and alarm the operator, update the controller parameters and provides an oscilloscopic view of the control parameters in real-time and buffered mode. The communication of the control parameters were implemented using a common industry protocol MODBUS for TMS320F28234 DSP processor using RS485 serial communication standard.