FX3U-ENET-L USER'S MANUAL - Automation Systems and Controls

7FIXED BUFFER COMMUNICATION (WITH THE NO PROCEDURECONTROL METHOD)MELSEC-FDatareceivingRead the word countfor the received dataand receive data2)FROMinstructionNotice the receive statusand receive completionof the fixed bufferBFM#1611RBFM#1611=0001HW3) 0002HR4)0004H(Success)/0008H(Error issued)1)Data receivingACK(only in TCP)1) Upon receiving data from the designated external device (set in the openprocessing), the Ethernet module processes the following.• Stores the received data to the fixed buffer (No. 2) area.(Area beginning from the head address of the target fixed buffer + 1)• Stores the data length to the head address area of the target fixedaddress (*1)• Fixed buffer communication receive results (BFM#1611) : 0001H• Fixed buffer receive status signal (BFM#20485 b1) : ON*1 The received data length is expressed by a byte count.When an odd number of data bytes is received, the last byte ofreceived data is stored at the lower byte of the last data storage area.(The higher byte becomes a non-constant value.)2) Execute the FROM instruction to read out the receive byte length andreceive data to the PLC.3) Execute the TO instruction to write "0002H" in the fixed buffercommunication receive results (BFM#1611).4) Result of the receiving processing is indicated.POINT(1) The destination setting (see Section 5.5) for a connection whose parametersare set in FX Configurator-EN-L becomes valid when the open completionsignal (BFM#20480 corresponding bit) of the Ethernet module switches fromoff to on.(2) When data is received and the data in the buffer memory's fixed buffer is set,BFM #1610, #1611 is set to "0001H".(3) At abnormal data receiving, each buffer memory status becomes as follows.• Fixed buffer receive completion signal (BFM#20485 b1) remains off.• Fixed buffer communication receive results (BFM#1611): 0008H• Data is not stored in the fixed buffer (No.2) area.7 - 77 - 7