Omega OMB-DAQBOARD-3000 User Manual

Glossary 

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A collection of scans acquired at a specified rate as controlled by the sequencer. 

A signal of varying voltage or current that communicates data.  

A circuit or device that converts analog values into digital values, such as binary bits, for use in 

digital computer processing. 

Application Program Interface.  The interface program within the Daq system’s driver that 

includes function calls specific to Daq hardware and can be used with user-written programs 

(several languages supported). 

A range of analog signals with positive and negative values (e.g., -5 to +5 V); see unipolar. 

Buffer refers to a circuit or device that allows a signal to pass through it, while providing 

isolation, or another function, without altering the signal.  Buffer usually refers to: 

(a)  

A device or circuit that allows for the temporary storage of data during data transfers.  

Such storage can compensate for differences in data flow rates.  In a FIFO (First In - First 

Out) buffer, the data that is stored first is also the first data to leave the buffer. 

(b)  

A follower stage used to drive a number of gates without overloading the preceding stage. 

(c)  

An amplifier which accepts high source impedance input and results in low source 

impedance output (effectively, an impedance buffer). 

An amplifier used primarily to match two different impedance points, and isolate one stage from 

a succeeding stage in order to prevent an undesirable interaction between the two stages. 

(Also see, Buffer). 

In reference to Daq devices, channel simply refers to a single input, or output entity. 

In a broader sense, an input channel is a signal path between the transducer at the point of 

measurement and the data acquisition system.  A channel can go through various stages 

(buffers, multiplexers, or signal conditioning amplifiers and filters).  Input channels are 

periodically sampled for readings. 

An output channel from a device can be digital or analog. Outputs can vary in a programmed 

way in response to an input channel signal. 

Common mode pertains to signals that are identical in amplitude and duration; also can be used 

in reference to signal components. 

Common mode voltage refers to a voltage magnitude (referenced to a common point) that is 

shared by two or more signals.  Example: referenced to common, Signal 1 is +5 VDC and 

Signal 2 is +6 VDC.  The common mode voltage for the two signals is +5.5 VDC [(5 + 6)/2]. 

An undesired transfer of signals between systems or system components.  Crosstalk causes 

signal interference, more commonly referred to as noise. 

A digital signal is one of discrete value, in contrast to a varying signal.  Combinations of binary 

digits (0s and 1s) represent digital data. 

A circuit or device that converts digital values (binary bits), into analog signals. 

A DIP switch is a group of miniature switches in a small Dual In-line Package (DIP).  Typically, 

users set these switches to configure their particular application. 

The differential mode measures a voltage between 2 signal lines for a single channel.  (Also see 

single-ended mode).