GP-Pro Ex Reference Manual - 38.9.4.1 Function for read/write

INT WINAPI ReadDeviceBit(LPCSTR sNodeName,LPCSTR sDeviceName,WORD* owData,WORD wCount);

INT WINAPI ReadDevice16(LPCSTR sNodeName,LPCSTR sDeviceName,WORD* owData,WORD wCount);

INT WINAPI ReadDevice32(LPCSTR sNodeName,LPCSTR sDeviceName,DWORD* odwData,WORD wCount);

INT WINAPI ReadDeviceBCD16(LPCSTR sNodeName,LPCSTR sDeviceName,WORD* owData,WORD wCount);

INT WINAPI ReadDeviceBCD32(LPCSTR sNodeName,LPCSTR sDeviceName,DWORD* odwData,WORD wCount);

INT WINAPI ReadDeviceFloat(LPCSTR sNodeName,LPCSTR sDeviceName,FLOAT* oflData,WORD wCount);

INT WINAPI ReadDeviceDouble(LPCSTR sNodeName,LPCSTR sDeviceName,DOUBLE* odbData,WORD wCount);

INT WINAPI ReadDeviceStr(LPCSTR sNodeName,LPCSTR sDeviceName,LPSTR psData,WORD wCount);

INT WINAPI ReadDevice(LPCSTR sNodeName,LPCSTR sDeviceName,LPVOID pData,WORD wCount,WORD wAppKind);

INT WINAPI ReadDeviceVariant(LPCSTR sNodeName,LPCSTR sDeviceName,LPVARIANT pData,WORD wCount,WORD wAppKind);

INT WINAPI WriteDeviceBit(LPCSTR sNodeName,LPCSTR sDeviceName,WORD* pwData,WORD wCount);

INT WINAPI WriteDevice16(LPCSTR sNodeName,LPCSTR sDeviceName,WORD* pwData,WORD wCount);

INT WINAPI WriteDevice32(LPCSTR sNodeName,LPCSTR sDeviceName,DWORD* pdwData,WORD wCount);

INT WINAPI WriteDeviceBCD16(LPCSTR sNodeName,LPCSTR sDeviceName,WORD* pwData,WORD wCount);

INT WINAPI WriteDeviceBCD32(LPCSTR sNodeName,LPCSTR sDeviceName,DWORD* pdwData,WORD wCount);

INT WINAPI WriteDeviceFloat(LPCSTR sNodeName,LPCSTR sDeviceName,FLOAT* pflData,WORD wCount);

INT WINAPI WriteDeviceDouble(LPCSTR sNodeName,LPCSTR sDeviceName,DOUBLE* pdbData,WORD wCount);

INT WINAPI WriteDeviceStr(LPCSTR sNodeName,LPCSTR sDeviceName,LPCSTR psData,WORD wCount);

INT WINAPI WriteDevice(LPCSTR sNodeName,LPCSTR sDeviceName,LPVOID pData,WORD wCount,WORD wAppKind);

INT WINAPI WriteDeviceVariant(LPCSTR sNodeName,LPCSTR sDeviceName,LPVARIANT pData,WORD wCount,WORD wAppKind);

INT WINAPI ReadSymbol(LPCSTR sNodeName,LPCSTR sSymbolName,LPVOID oReadBufferData);

INT WINAPI ReadSymbolVariant(LPCSTR sNodeName,LPCSTR sSymbolName,LPVARIANT pData);

INT WINAPI WriteSymbolD(LPCSTR sNodeName,LPCSTR sSymbolName,LPVOID pWriteBufferData);

INT WINAPI WriteSymbolVariantD(LPCSTR sNodeName,LPCSTR sSymbolName,LPVARIANT pData);

sDeviceName: Directly describes the symbol names and device addresses registered in GP-Pro EX.

The following table shows the data types that you can specify when using symbols in each function.

Function	Symbol data type
	Bit	16 Bit		32 Bit		Float	Double	String
	Bit	Signed/ Unsigned/ Hexadecimal	BCD	Signed/ Unsigned/ Hexadecimal	BCD	Float	Double	String
XXXDeviceBit	○	—	—	—	—	—	—	—
XXXDevice16	—	○	—	—	—	—	—	—
XXXDevice32	—	—	—	○	—	—	—	—
XXXDeviceBCD16	—	—	○	—	—	—	—	—
XXXDeviceBCD32	—	—	—	—	○	—	—	—
XXXDeviceFloat	—	—	—	—	—	○	—	—
XXXDeviceDouble	—	—	—	—	—	—	○	—
XXXDeviceStr	—	—	—	—	—	—	—	○
XXXDevice	○	○	○	○	○	○	○	○

Defines the destination pointer for values that are read or values that are written. For each function, please define the corresponding data format pointer.

Data types for access	Argument type
Bit Data	WORD * pwData
16 bit data	WORD * pwData
32 bit data	DWORD * pdwData
16-bit BCD data	WORD * pwData
32-bit BCD data	DWORD * pdwData
Single float number data	FLOAT * pflData
Double float number data	DOUBLE * pdbData
Text data	LPTSTR psData
General data	LPVOID pData
General data (for VB)	LPVARIANT pData

For the Read/WriteDeviceStr function, the amount of text data is expressed in single-byte units. If the symbol refers to a 16-bit device, use two characters to specify the number. If it refers to a 32-bit device, use four characters.
The following table shows the maximum amount of read/write data.

Data types for access	Read/Write
Bit Data	255
16 bit data	1020
32 bit data	510
16-bit BCD data	1020
32-bit BCD data	510
Single float number data	510
Double float number data	255
Text data	1020 characters (Single-byte)

To specify the Data Type Value, you can either directly specify the value or specify using a constant name. For more details, please refer to the following.

38.9.5.1 Data Type

pwData stores the same amount of data as in wCount starting from D0 bit.
For example, when wCount = 20

	F	E	D	C	B	A	9	8	7	6	5	4	3	2	1	0
PwData	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1
PwData+1	*	*	*	*	*	*	*	*	*	*	*	*	20	19	18	17

it is more efficient to read/write in 16/32 bits using Read/WriteDevice16 and Read/WriteDevice32 than using Read/WriteDeviceBit.
"*" contains undefined values. Mask the value using an application program.

Use these functions for handling data as BCD internally in the device/PLC. Note that data (pxxData contents) to be sent to /received from the functions is binary data, not BCD.
BCD conversion is performed in the [WinGP SDK]. Negative numbers cannot be handled.

For variables to receive text data, secure sufficient data space to receive the data.