2.1.2 - OpenS | LabJack
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2.1.2 - OpenS

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.


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


DeviceType [in]
A string containing the type of the device to be connected:
"ANY" - Open any supported LabJack device type
"T4" - Open a T4 device
"T7" - Open a T7-series device
"TSERIES" - Open a T4 or T7
"DIGIT" - Open a Digit-series device
For other LabJack devices, see What driver/library should I use with my LabJack?
ConnectionType [in]
A string containing the type of connection desired (USB or TCP):
"ANY", "USB", "TCP", "ETHERNET", or "WIFI"
Additional UDP options:
"NETWORK_UDP", "ETHERNET_UDP", "WIFI_UDP". Also "ANY_UDP" is available in LJM 1.2100 and later.
Additional 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.


Relevant Functions

LJM_OpenS and LJM_Open are essentially the same, except that LJM_Open uses integer parameters for DeviceType and ConnectionType rather than string  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#] Opening a T7 via TCP using LJM_OpenS

int LJMError;
int handle;
LJMError = LabJack.LJM.OpenS("T7", "Ethernet", "ANY", ref handle);

[C/C++] Opening a T7 via TCP using LJM_OpenS

int LJMError;
int handle;
LJMError = LJM_OpenS("T7", "TCP", "ANY", &handle);