and old question -- communication between pc and plc

[Patrick Leung]

All, Sorry that I have ask an old question. I am going to develop an application that perform and read/write Fx-2N PLC through RS232C port on PC to FX2N-232-BD. But I have trouble about this. I am using a cable that made by myself. The wiring is the same as FX Communications Modules RS232C, RS-485, RS-422 page 27 section 3.2.1 (sorry that I don't know how to attach this page). D8120 = 18577 (H4891). i.e. Link protocol, data bits = 8, Parity = none, stop bits = 1, transfer rate = 19200, no check sum, control procedure = format 1. But I cannot perform any read/write on PLC. The command I write to PLC is "ENQ00FFBRAX004005" (05h 30h 33h 46h 46h 42h 52h 30h 58h 30h 30h 34h 30h 30h 35h in hex. The hex code is quite strange, but I find the lookup table of ASCII character hex code from the same manual.). I have also add a COT (04h) at the end of command string, but also fail to communicate. The RXD LED on FX2N-232-BD is flashing while I send command to it. But the TXD do not light at all. I have check the manual diagnostic section, it tell me that I need to check the PLC station number and baud rate. But I also cannot find any mistake. p.s. When I set the D8120 to 0, I can use the FX2N-232-BD to perform upload/download operation at SW0PC-FXGP/WIN-E software. Need for help, please. Thanks. Patrick

[Guest aprendis]

check the fx-232cab-1 cable. this is for connects pc to FX1N-232-BD AND FX2N-232-BD. IS A SERIAL CABLE (DB9 F TO DB9 F) F= FEMALE If you want to make it use this diagram. . _________ / 5 ............1 \ \9_______6/ 1 nc 2 to 3 3 to 2 4 to 6&8 5 to 5 6&8 to 4 7 nc 9 nc Edited July 5, 2006 by aprendis

[Patrick Leung]

Thanks. aprendis. p.s. when I use the currently using cable, I can perform RS instruction in my own developed software. i.e. PLC will response my RS command.