CntSamplingSetBuffer

Function

Sets the sampling buffer.

Format

Ret = CntSamplingSetBuffer ( Id , Buffer , ChNum , ScanNum , IsRing )

Parameters

Id [ VB.NET: Short ] [ C, C++: short ] [ C#: short ] [ Python: ctypes.c_short ]
Specify the device ID retrieved from CntInit.

Buffer [ VB.NET: IntPtr ] [ C, C++: unsigned long * ] [ C#: IntPtr ] [ Python: ctypes.POINTER(ctypes.c_ulong) ]
Specify the base address of buffer.

ChNum [ VB.NET: Short ] [ C, C++: short ] [ C#: short ] [ Python: ctypes.c_short ]
Specify the number of channels in buffer.

ScanNum [ VB.NET: Integer ] [ C, C++: unsigned long ] [ C#: uint ] [ Python: ctypes.c_ulong ]
Specify the scan number of buffer.

Device Name

Available Range

CNT-3204IN-USB

ChNum(number of channels) * ScanNum(number of data) * 4Byte(data unit) <= 64MByte

CNT32-8M(PCI)
CNT32-4MT(LPCI)
CNT-3204MT-LPE
CNT-3208M-PE

These devices implement bus master transfers with a 32-bit bus width.
Bus master transfers with a 32-bit bus width are subjected to buffer size restrictions depending on the OS used.

The hardware is designed to enable bus master transfers of up to 64MBytes.
However, it cannot be set up to 64MBytes due to OS restrictions.
Please note. The details are as follows.

OS used	Range of settings
Windows 10 Version 1703 or later (including Windows 11)	ChNum * ScanNum * 4Byte <= 2MByte
Windows 10 Version 1607 or earlier	ChNum * ScanNum * 4Byte <= 1MByte

*Depending on how the physical address space is mapped, it may not be possible to set the bus master buffer size up to the maximum area.

IsRing [ VB.NET: Short ] [ C, C++: short ] [ C#: short ] [ Python: ctypes.c_short ]
Sets whether the buffer is used once per transfer, or is used as a ring buffer.

Definition	Value	Description
CNTS_WRITE_ONCE	0	Once transfer
CNTS_WRITE_RING	1	Infinite time transfer

Return Value

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

Definition	Value	Description
CNT_ERR_SUCCESS	0	Normality completion
CNT_ERR_SYS_RECOVERED_FROM_STANDBY	7	Execute the function CntResetDevice to return from the standby mode.
CNT_ERR_DLL_INVALID_ID	10001	Invalid ID was specified.
CNT_ERR_DLL_CALL_DRIVER	10002	CNT driver can't be called (Failed in the device I/O control).
CNT_ERR_DLL_BUFF_ADDRESS	10101	Invalid data buffer address.
CNT_ERR_SYS_MEMORY	20000	It failed in memory allocation for the object preparation.
CNT_ERR_SYS_NOT_SUPPORTED	20001	This function can't be used by this device.
CNT_ERR_SYS_USING_OTHER_PROCESS	20003	Cannot use because another process is using the device.
CNT_ERR_SYS_BUFFER	21100	Because the buffer was too large, it was not possible to secure it.
CNT_ERR_SYS_LOCK_MEMORY	21101	The memory cannot be locked.
CNT_ERR_SYS_SEQUENCE	21102	Execution procedure error

The others: (See also: Details of Error Code)

Remarks

Execute the buffer setting before transfer starts every time.

For devices with the bus master transfer function, in the specification of hardware, the buffer size can be set up to 64MByte,
depending on how the buffer area maps to physical address space, 64MByte area maybe cannot be set,
63MByte becomes the real upper limit.

For USB devices, depending on the memory status of system, there is a possibility that 64MByte area can not be set.

The execution procedure error occurs when this function is executed in sampling.
Execute it after confirming sampling was completed.

Example

Sets the buffer for 10000 data to channel 0. The buffer is used for the infinite transfer.

VB.NET	Refer to Note of Using Visual Basic .NET
C, C++	long Ret; unsigned long Buffer[10000]; Ret = CntSamplingSetBuffer ( Id , &Buffer[0] , 1 , 10000 , CNTS_WRITE_RING );
C#	Refer to Note of Using Visual C#
Python	Ret = ctypes.c_long() BufferType = ctypes.c_ulong * 10000 Buffer = BufferType() Ret.value = ccnt.CntSamplingSetBuffer ( Id , Buffer , 1 , 10000 , ccnt.CNTS_WRITE_RING )