GE AF-300 P11 User Manual

Contents

12-1Data subject to change without notice 7/07. © 2007 GE DrivesThe serial interface supports operation, configuration and monitoring of drive functions through an EIA/RS485 connec-tion. The serial interface is based on Modbus RTU protocol. This protocol allows the drive to function as an RTU slaveon an industrial network.12.1 Transmission SpecificationItem SpecificationPhysical level EIA/RS485Transmission distance 500 m max.Number of nodes 32 totalTransmission speed 19200, 9600, 4800, 2400 [bits/s]Transmission mode Half duplexTransmission protocol Modbus RTUCharacter code BinaryCharacter length 8 bitsError check CRC12.2 ConnectionConnection methodUse shielded wire and connect to the control terminals (DX-, DX+ and SD). A termination resistor should be addedbetween the data lines on the each end of the network. The value of the termination resistor depends on the character-istic impedance of the cable. A common value for termination resistors is 120 ohms.Control terminalsTerminalmarking Terminal name Function descriptionDX+ RS485 communication data (+) Input/output terminals for RS485DX- RS485 communication data (–) communication.SD Cable shield Electrically floating12.3 Serial Interface ConfigurationDrive function codes H30 to H39 are used to configure the serial interface parameters, such as device address, baudrate and error response.12.4 Modbus RTU FunctionsThe following RTU functions are supported. The maximum number of consecutive parameters for function 03 and 16messages is 16.Code Description03 Read Holding Registers (16 registers maximum)06 Preset Single Register16 Preset Multiple Registers (16 registers maximum)12. RS485 Modbus RTU Serial Communications