FR-A701 INSTRUCTION MANUAL (Applied) - Automation Systems ...

Communication operation and setting4.24.6 Modbus-RTU communication specifications (Pr. 331, Pr. 332, Pr. 334, Pr. 343,Pr. 539, Pr. 549)Using the Modbus-RTU communication protocol, communication operation or parameter setting can beperformed from the RS-485 terminals of the inverter.ParameterName Initial Value Setting Range DescriptionNumber331RS-485 communication stationnumber332 RS-485 communication speed 96334RS-485 communication paritycheck selection020 Broadcast communication is selected.1 to 2473, 6, 12, 24, 48,96, 192, 384343 Communication error count 0 ⎯539Modbus-RTU communicationcheck time interval9999549 Protocol selection 001200.1 to 999.8s99990Specify the inverter station number.Set the inverter station numbers when twoor more inverters are connected to onepersonal computer.Set the communication speed.The setting value × 100 equals thecommunication speed.For example, the communication speed is9600bps when the setting value is "96".Without parity checkStop bit length 2bitsWith odd parity checkStop bit length 1bitWith even parity checkStop bit length 1bitDisplay the number of communicationerrors during Modbus-RTUcommunication. Reading onlyModbus-RTU communication can bemade, but the inverter will come to trip inthe NET operation mode.Set the interval of communication check time.(same specifications as Pr. 122)No communication check (signal lossdetection)Mitsubishi inverter (computer link)protocol1 Modbus-RTU protocolCAUTIONWhen Modbus-RTU communication is performed from the master with address 0 (station 0) set, broadcast communication isselected and the inverter does not send a response message to the master.When response from the inverter is necessary, set a value other than "0" in Pr. 331 (initial value 0).Some functions are invalid for broadcast communication. (Refer to page 318)REMARKS⋅ When using the Modbus-RTU protocol, set Pr. 549 Protocol selection to "1".⋅ When the communication option is fitted with Pr. 550 NET mode operation command source selection set to "9999" (initial value), thecommand source (e.g. run command) from the RS-485 terminals is invalid. (Refer to page 292)(1) Communication specifications⋅ The communication specifications are given below.RelatedItemDescriptionParametersCommunication protocol Modbus-RTU protocol Pr. 549Conforming standard EIA-485 (RS-485) ⎯Number of inverters connected 1: N (maximum 32 units), setting is 0 to 247 stations Pr. 331Communication speed Can be selected from 300, 600, 1200, 2400, 4800, 9600, 19200 and 38400bps Pr. 332Control protocol Asynchronous system ⎯Communication method Half-duplex system ⎯Character system Binary(fixed to 8 bits) ⎯CommunicationspecificationsStart bit 1bit ⎯Stop bit lengthParity checkSelect from the following three types⋅ No parity, stop bit length 2 bits⋅ Odd parity, stop bit length 1 bit⋅ Even parity, stop bit length 1 bitError check CRC code check ⎯Terminator Not used ⎯Waiting time setting Not used ⎯Pr. 334316