Watchdog

Since I last posted it apears that by juggling with D8120 you can set the protocol that an FX will communicate with. Witht the right settings (and I have yet to work through that one) the FX will use the old C24 Format 1 protocol, which is what everyone refers to as the 16bit protocol. If this works then I think I have my solution. I will post with full details if I can get this baby going. Thanks Panic Mode, an earlier post you made elsewhere put me on to the download section, which in it's turn pointed me in this direction. You move in mysterious ways sir

The latest info I can find is that the serial protocol that I am using to access the FX PLC is 8 bit, and is the old Mitsubishi F1 RS232 unit protocol. Aparently this limits access to the D regs at D999. Sigh. Aparently there is a 16 bit protocol (not the programming protocol) that will allow access to D1000 and above - but unfortunately this protocol may not be in the public domian. (So how do SCADA suppliers get hold of it then I wonder - yet another sigh). If it is inthe public domain anywhere I would dearly love as link to it. I would be happy to furnish a Python interface or a VB interface to all and sundry buckshee if I can get this going. More later. Watchdog.

Hardware Background Info ... FX (CPU V3.3) Medoc 1.64 or 2.04 Accessing PLC with Visual basic My Problem ... I am trying to write to the file register area D1300 using a visual basic program. The program is as old as the hillls (by that assume it is reliable - honest). I can monitor the string being sent as it is sent, so I can see that D1300 is being written to, and the PLC accepted it as OK. However, I think it may be dumping the request internally because when I do a BMOV from D1300 to D170 and read back D170 all I get in D170 is FFh The first file register block has been enabled in Medoc (D1000- D1499) and there is room in my code (prog length is sub 1500 steps) for the BMOV. EDIT - I know I can use BMOV on FX1n,FX2n and FX2nc but I need to be able to do this on one of the old FX's. My Experience ... Good on serial comms, Intel asssembler and VB programmer by profession. Been working on FX's for 10 years but never needed to access the file registers before. Hope one of you guys can help me here. Thanks in advance