DAQ Dictionary: T

Our newest edition of DAQ dictionary explains terms from data acquisition starting with the letter T. Enjoy and learn!

Talker

A device on the GPIB (general purpose interface bus) that sends information to a Listener on the bus.

TCP/IP

Transmission Control Protocol/Internet Protocol. Communications protocols used to connect hosts on the internet.

Text Format

Text format refers to information in the ASCII character set. It is unformatted. Each byte in the file contains one character that conforms to the standard ASCII code.

Thermal

The coefficient of Resistance The change in resistance of a semiconductor per unit change in temperature, over a specific range of temperature.

Thermal Conductivity

A measure of the rate of flow of thermal energy through a material in the presence of a temperature gradient. Materials with high electrical conductivities tend to have high thermal conductivities.

Thermocouple

Popular temperature sensor because of its low cost, wide operating range, and ruggedness. Consists of two dissimilar metals joined together, making a continuous loop. When one junction has a different temperature from the other an electromotive force (voltage) occurs. There are several types of thermocouples, constructed from different metals and with differing temperature ranges and accuracies.

Thermistor

A temperature sensor. The name comes from the thermal resistor. It is a semiconductor that exhibits a large change in resistance as a function of temperature. Most thermistors exhibit a negative temperature coefficient, where resistance decreases as temperature rises. These are referred to as NTC thermistors.

Throughput

A number of results produced per unit time.

Timeout

The timing software should wait for a reply from the instrument before giving up. If no reply is received in this time, an error may be declared. To avoid spurious timeouts set to between five and ten times the normal response time.

Timestamp

The information added to data to indicate the time at which it was collected.

Transducer

A device which converts a physical quantity into an electrical signal. Examples include thermocouples and photocells. Most sensors are also transducers.

Transient

A short surge of current or voltage, often occurring before steady-state conditions have become established.

Trigger

A trigger is something that causes a data acquisition system to start collecting data. It may be as simple as pressing a software button or a set of conditions which when met trigger data capture (internal triggers), or an externally generated, hardware signal (an external trigger).

Truncation

Rejection of the final digits in a number, thus lessening the precision but not necessarily the accuracy.

TTL

Abbreviation for transistor-transistor logic. Referring to logic circuits consisting of two or more directly interconnected transistors, to provide conditional switching capability.

TTL-Compatible

For digital input circuits, a logic 1 is obtained for inputs of 2.0 to 5.5 V which can source 40 microA, and a logic 0 for inputs of 0 to 0.8 V which can sink 1.6 mA. For digital output signals, a logic 1 is represented by 2.4 to 5.5 V with a current source capability of at least 400 microA; and a logic 0 by 0 to 0.6 V with a current sink capability of at least 16 mA.

T-Type Thermocouple

Copper-constantan thermocouple with a temperature range of -200 to 400 oC.

Twisted Pair

A cable that consists of individual wires wrapped around each other for carrying telephone or computer data. Reduces pickup noise levels in signals.