LJM Constants

Subsections

A note on language wrapper differences

The constants are accessed in different ways, depending on which LJM language wrapper is being used.

C/C++

LJM constants begin with the prefix LJM_. For example, use LJM_READ.

LabVIEW

LJM constants begin with the prefix LJM_. For example, use LJM_READ.

Python

LJM constants are located in the namespace labjack.ljm.constants and do not begin with the LJM_ prefix. For example:

import labjack print(labjack.ljm.constants.READ) # Prints 0

Or, for a shorter version:

from labjack.ljm import constants as ljmc print(ljmc.READ) # Prints 0

.NET

LJM constants are located in the namespace LabJack.LJM.CONSTANTS and do not begin with the LJM_ prefix. For example:

// C# import LabJack; // ... Console.WriteLine(LJM.CONSTANTS.READ); // Prints 0

' Visual Basic Imports LabJack ' ... Console.WriteLine(LJM.CONSTANTS.READ) ' Prints 0

Delphi

LJM constants begin with the prefix LJM_. For example, use LJM_READ.

Java

LJM constants are located in the namespace com.labjack.LJM.Constants and do not begin with the LJM_ prefix. For example:

import com.labjack.LJM; // ... System.out.println(LJM.Constants.READ); // Prints 0

Node.js

LJM constants are located in ljswitchboard-ljm_driver_constants/lib/driver_constants.js and generally begin with the prefix LJM_. For example,

var ljmc = require('ljswitchboard-ljm_driver_constants'); console.log(ljmc.LJM_READ)

Visual Basic 6 and VBA

LJM constants begin with the prefix LJM_. For example, use LJM_READ.

LJM Configuration Constants

The LJM configuration constants configure LJM behavior, such as timeouts. For more information, see the Library Configuration Functions.

LJM Constants

Used to specify if reading or writing

READ = 0
WRITE = 1

Used to specify data type for parameters

UINT16 = 0
UINT32 = 1
INT32 = 2
FLOAT32 = 3

BYTE = 99
STRING = 98

The STRING data type has the following max size, not including the automatic null-terminator:

STRING_MAX_SIZE = 49

May be used to initialize the ErrorAddress parameter of the multiple value functions:

INVALID_NAME_ADDRESS = -1

The maximum size of the ErrorString of LJM_ErrorToString:

MAX_NAME_SIZE = 256

As an entry of the aData parameter of LJM_eStreamRead, indicates a value was skipped due to auto-recovery:

DUMMY_VALUE = -9999

Device types used to specify which LabJack device to open

dtANY = 0
dtUE9 = 9
dtU3 = 3
dtU6 = 6
dtT4 = 4
dtT7 = 7
dtTSERIES = 84
dtSKYMOTE_BRIDGE = 1000
dtDIGIT = 200

Common connection types used to specify connect to be used when opening a device

ctANY = 0
ctUSB = 1
ctTCP = 2 // Ethernet or WiFi
ctETHERNET = 3 // TCP
ctWIFI = 4 // TCP

Uncommon connection types

ctNETWORK_UDP = 5
ctETHERNET_UDP = 6
ctWIFI_UDP = 7
ctNETWORK_ANY = 8 // TCP or UDP
ctETHERNET_ANY = 9 // TCP or UDP
ctWIFI_ANY = 10 // TCP or UDP
ctANY_UDP = 11 // Available in LJM 1.2100 and later

Constants related to opening devices

NO_IP_ADDRESS = 0
NO_PORT = 0
TCP_PORT = 502
ETHERNET_UDP_PORT = 52362
WIFI_UDP_PORT = 502
UNKNOWN_IP_ADDRESS = -1

DEMO_MODE = "-2"

idANY = 0

The size of the arrays of LJM_ListAll

LIST_ALL_SIZE = 128

Timeout constants

NO_TIMEOUT = 0
DEFAULT_USB_SEND_RECEIVE_TIMEOUT_MS = 2600
DEFAULT_ETHERNET_OPEN_TIMEOUT_MS = 1000
DEFAULT_ETHERNET_SEND_RECEIVE_TIMEOUT_MS = 2600
DEFAULT_WIFI_OPEN_TIMEOUT_MS = 1000
DEFAULT_WIFI_SEND_RECEIVE_TIMEOUT_MS = 4000