I'm using version 3.52 with a SLC 500 connected with a DF1 connection with a RS232 cable connected to a RS232 to USB cable. It works fine when the cable is connected. When the cable is not connected on the PLC end, the HMI start time is long and the form is slow to react to user input. The startup time increases with the number of controls on the form. With about fourty controls, it takes about two minutes for the form to appear on screen.
It looks like most of the startup time is spent inside line 340 of DF1Comm.vb (inside the dll) :
result = DLL(MyDLLInstance).SendData(CommandPacke, MyNode, TargetNode)
When that line executes with one control on the form, the following output appears in the ouput window of the debugger :
The thread '<No Name>' (0x3d4) has exited with code 0 (0x0).
The thread '<No Name>' (0x1e48) has exited with code 0 (0x0).
The thread '<No Name>' (0x129c) has exited with code 0 (0x0).
The thread '<No Name>' (0x1458) has exited with code 0 (0x0).
The thread '<No Name>' (0x1d1c) has exited with code 0 (0x0).
The thread '<No Name>' (0x1da4) has exited with code 0 (0x0).
The thread '<No Name>' (0x1510) has exited with code 0 (0x0).
The thread '<No Name>' (0x1648) has exited with code 0 (0x0).
The thread '<No Name>' (0xac8) has exited with code 0 (0x0).
The thread '<No Name>' (0x1f04) has exited with code 0 (0x0).
The thread '<No Name>' (0x1da0) has exited with code 0 (0x0).
The thread '<No Name>' (0x818) has exited with code 0 (0x0).
The thread '<No Name>' (0x1eac) has exited with code 0 (0x0).
The thread '<No Name>' (0x1d20) has exited with code 0 (0x0).
The thread '<No Name>' (0x1d38) has exited with code 0 (0x0).
The thread '<No Name>' (0x1aec) has exited with code 0 (0x0).
The thread '<No Name>' (0x1824) has exited with code 0 (0x0).
The thread '<No Name>' (0x494) has exited with code 0 (0x0).
The thread '<No Name>' (0x1b7c) has exited with code 0 (0x0).
The thread '<No Name>' (0x1640) has exited with code 0 (0x0).
After that, the following line appears in the output window of the debugger :
A first chance exception of type 'MfgControl.AdvancedHMI.Drivers.Common.PLCDriverException' occurred in AdvancedHMIDrivers.dll
Those lines repeat every 10 seconds. If there are many controls on the form, this seems to cause a slowdown of the application.