For the first the since we’ve started publishing DAQ dictionary, we have an article with 3 letters in it: J,K and L. Enjoy and get even more familiar with data acquisition!
J-Type Thermocouple
Iron-constantan thermocouple with a temperature range of 0 to 750 oC.
k
A symbol for a thousand, from a kilo.
K
A unit of stored data. 1K = 210 = 1024. Also, stands for a degree on the Kelvin temperature scale.
Kelvin
A temperature scale which is one of the seven base units in the International System of Units (SI). The symbol is K.
K-Type Thermocouple
Chromel-Alumel thermocouple with a temperature range of -200 to 1200 oC.
A Line Feed
A “non-printing” character which often terminates a message from an instrument plugged into the computer’s COM port.
LAN
Local area network. A data communication system connecting devices in the same vicinity. Data is transferred without the use of public communications. Examples of LANs are Ethernet, token ring and Modbus.
Least Significant Bit, LSB
In a binary number, the 1 or 0 furthest to the right.
LIFO
Last in first out. Describes a stack method of data storage.
LIMS
Laboratory information management system.
Linearity
Ideally, an A-D or D-A converter converts the input or output range into equal steps. In practice, the steps are not exactly equal. Linearity, or non-linearity, is a measure of how close the steps approach equality.
Load Cell
A transducer which converts a force into an electrical signal. It normally comprises four strain gauges in a Wheatstone bridge arrangement.
Loopback Test
A signal is sent out and returned as a way to determine whether the COM port is working correctly. It is used to troubleshoot serial communications.
Low Pass Filter
This lets through the lower frequencies and attenuates the higher frequencies. Choose the cut-off frequency to be compatible with the unwanted frequencies, the frequencies present in the signal you are measuring, and the sampling rate of the analog-to-digital converter.
LVDT
Linear Variable Differential Transformer. Used in measuring devices that convert changes in a physical position to an electrical output.
