2.1.1 - Open | LabJack
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2.1.1 - Open

Opens a desired LabJack and associates a device handle number (connection ID).  The device handle may then be passed as an input to other functions.


                      int DeviceType,
                      int ConnectionType,
                      const char * Identifier,
                      int * Handle)


DeviceType [in]
An integer containing the type of the device to be connected:
LJM_dtANY (0) - Open any supported LabJack device type
LJM_dtT4 (4) - Open a T4 device
LJM_dtT7 (7) - Open a T7-series device
LJM_dtTSERIES (84) - Open a T4 or T7
LJM_dtDIGIT (200) - Open a Digit-series device
For other LabJack devices, see What driver/library should I use with my LabJack?
ConnectionType [in]
An integer containing the type of connection desired:
LJM_ctANY (0), LJM_ctUSB (1), LJM_ctTCP (2), LJM_ctETHERNET (3), LJM_ctWIFI (4)
Other UDP options:
Also, LJM_ctANY_UDP (11) is available in LJM 1.2100 and later.
Other TCP or UDP options:
Identifier [in]
A string that may identify the device to be connected.  To open any device, use LJM_idANY (or the string "ANY").  To specify an identifier, use a serial number, IP address, or device name.  See Identifier Parameter for more information. If you don't have a device available, you can use LJM_DEMO_MODE (or the string "-2") to open a fake device.
Handle [out]
The new handle that represents the device connection.  


LJM errorcode or 0 for no error.

Related Functions

LJM_Open and LJM_OpenS are essentially the same, except that LJM_OpenS uses string parameters for DeviceType and ConnectionType rather than integer parameters.

See LJM_GetHandleInfo to retrieve information about a handle.

See LJM_ListAll or LJM_ListAllS to find multiple devices.


See the notes in Opening and Closing.

When the ConnectionType parameter of this function is network-based, this function will check the IP addresses listed in LJM_SPECIAL_ADDRESSES_FILE.


[C/C++] Opening the first found T7, using LJM_Open

int LJMError;
int handle;
LJMError = LJM_Open(7, 0, "ANY", &handle);