The Gripper can be controlled by Modbus RTU directly with RS485 or over USB using the ACC-ADT-USB-RS485. This section is intended to provide guidelines for setting up a Modbus scanner that will adequately communicate with the Gripper.
For a general introduction to Modbus RTU and for details regarding the CRC algorithm, the reader is invited to read the Modbus over serial line specification and implementation guide available at: http://www.modbus.org/docs/Modbus_over_serial_line_V1.pdf.
For debugging purposes, the reader is also invited to download one of many free Modbus scanners such as the CAS Modbus Scanner from Chipkin Automation Systems available at: http://www.chipkin.com/cas-modbus-scanner.
Modbus RTU is a communication protocol based on a Big Endian byte order. Therefore, the 16-bit register addresses are transmitted with the most significant byte first. However, the data port is in the case of Robotiq products based on the Little Endian byte order. As such, the data parts of Modbus RTU messages are sent with the less significant byte first.
Modbus RTU specification and details can be found at www.modbus.org.