9.5 Sending/Receiving Flag Operation9-159.5 Sending/Receiving Flag Operation9.5.1 No Header (Start Code), Terminator (End Code) "CR":The “reception done” flag, the “sending active” flag, the GPSEND instruction, and theGPRECV instruction are related as follows:A B C CR D F G1 3 CRBCA3ONOFFONOFFONOFFONOFFE2A DAB BCA<1> <2> <3>EDEFDEFGD<2> <3> <4><1>Data receivedfrom externaldeviceSCUreceive bu fferNo. of bytesreceivedTransmitteddataReceive bu fferspecified usingGPRECV instructionReceptiondone flagX0, X1, X2, X3General-purposecommunicationSending active flagY8, Y9, YA, YBGPRECVinstructionexecutionGPSENDinstructionexecutionStoredWrite pointer Data can be received until eightreceive bu ffers are all filled up evenif the reception done flag is turned on.After GPRECV instruction isexecuted, reception doneflag turns off at the beginningof next scan or later.No. of bytes received The COM port has eight reception buffers. The reception process is continued after thereception done flag (X0, X1, X2, X3) turns ON. The reception done flag (X0, X1, X2) doesnot turn OFF immediately following the execution of GPRECV instruction. It will be turned offat the beginning of the next scan or later. After GPSEND instruction is executed, data transmission is started in several μs to severaltens of ms. For time before transmission is started, please refer to the communication cycletime (SM208-SM210) using the system monitor function.Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.clrwtr.com - Email: info@clrwtr.com
