AioSetAiEvent

Function

Sets the event factor of the window message notification that is related to the analog input.

Format

Ret = AioSetAiEvent ( Id , hWnd , AiEvent )

Parameters

Id [ VB.NET : Short ] [ C, C++ : short ] [ C# : short ] [ Python : ctypes.c_short ]
Specifies the ID retrieved from AioInit function.

hWnd [ VB.NET : IntPtr ] [ C, C++ : HWND ] [ C# : IntPtr ] [ Python : ctypes.wintypes.HANDLE ]
Specifies the window handle.

AiEvent [ VB.NET : Integer ] [ C, C++ : long ] [ C# : int ] [ Python : ctypes.c_long ]
Specifies the event factor from the following range in macro or value.
AiEvent has the following meanings in bit, it can be specified by a combination of these bits.

The event factor of using device buffer is different from using user buffer.

When "Event that the specified number of data are stored" is used, set the number of samplings that raises the event by using the AioSetAiEventSamplingTimes function. When "Event that the specified number of data are transferred" is used, set the transfer times that raises the event by using the AioSetAiEventTransferTimes function.

Return value

Ret [ VB.NET : Integer ] [ C, C++ : long ] [ C# : int ] [ Python : ctypes.c_long ]

Initial value

In all devices, AiEvent = 0 (Not use event)

Remarks

The event factor set in this function are notified as message to event message routine. 

The message type are as follows.

This function cannot be used on devices without the analog input function.
If the device is in operation, the function cannot be performed.
It cannot be used with callback routine (AioSetAiCallBackProc). 

For Ethernet devices
    If communication with the device is lost, the process will be unregistered and will no longer receive event notifications.
    If you want to perform event notification again, please make the settings again using this function.

Example

Sets "Event that device operation end" and "Event that the specified number of data are stored".

See also

AioGetAiEvent AioSetAiEventSamplingTimes AioGetAiEventSamplingTimes

Event Message Routine

When the event factor set by the AioSetAiEvent function occurs, the event message routine is called.

There are three(3) important values for arguments passed to event message routines. [Message ID], [Device ID], [Unique parameters for each event].
Details of each argument are as follows.

- Message ID (m.Msg property / message argument)

- Device ID (m.WParam property / wParam argument)

When you use multiple devices on the same PC, Please identify the device that generated the event by Device ID in the event message routine.

When you use only one(1) single device, you do not need to identify Device ID.
You can handle the process with [message number] and [specific parameters for each event] in the event message routine.

- Parameter peculiar to event

The way of writing the event message routine processing depends on the development language you are using.

The following are some examples of how to override the event message routine and the arguments.
For details, please refer to the documentation provided by Microsoft.

In Visual Basic .NET(WndProc)

The way to override

Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)

Please refer to the following three properties of the argument System.Windows.Forms.Message structure.

m.Msg: Message ID is passed.
m.WParam: Device ID is passed in lower 2 bytes. High 2 bytes aren't use now.
m.LParam: The parameter peculiar to event is passed.

In Visual C#(WndProc)

Please refer to the following three properties of the argument System.Windows.Forms.Message structure.

[System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name="FullTrust")]
protected override void WndProc (ref Message m)

Please refer to the following three properties of the argument Message structure.

m.Msg: Message ID is passed.
m.WParam: Device ID is passed in lower 2 bytes. High 2 bytes aren't use now.
m.LParam: The parameter peculiar to event is passed.

In Visual C++

The way to override

LRESULT CVC6Dlg::DefWindowProc(UINT message, WPARAM wParam, LPARAM lParam)

Please refer to the following three arguments on DefWindowProc.

message: Message ID is passed.
wParam: Device ID is passed in lower 2 bytes. Higher 2 bytes aren't used now.
lParam: The parameter peculiar to event is passed.