94Chapter 9 CommunicationA CD servo driver has the RS232 communication interface, which directly controls the working of theservo driver with the operation software of a host computer. If the servo driver needs to communicate with aProgrammable Logic Controller (PLC) or other controllers via the free RS485 communication interface, anRS232 to RS485 converter should be added on the driver side.Fig. 9-1 Communication cables between a PC and a servo driver9.1 Transport ProtocolThe RS-232C communication of the CD servo driver strictly follows a master/slave protocol. The hostcomputer can send any data to CD driver. The driver configured with ID No. will calculate such data andreturn a reply.Default communication settings for the CD servo driver are as follows:Baud rate = 38400 bpsData bits = 8Stop bits = 1No parity checkThis transport protocol uses a data packet with fixed length of10 bytes.ID 8 byte data CHKSbyte 0 byte 9The baud rate can be changed by setting d5.02, after changing the value, it is necessary to set d2.00 or d3.00to save it and reboot the system so that it will take effect.The transport protocol used by the RS-232 uses a data packet with fixed length of10 bytes.ID CHKS8 byte databyte 0 byte 9ID is the ID No. of the slaveCHKS =-SUM(byte0,…,byte8), CHKS is the last two digits of the calculation result.The host sends:ID CHKS8 byte host databyte 0 byte 9The slave sends/The host receives:
