Spectrum Controls 1746sc-INI4vi - Manual (Page 9)

Preface 5
channel to convert the data received from the processor to analog output
signals at the terminals.
Chassis – See rack.
Common mode rejection – The maximum level to which a common
mode input voltage appears in the numerical value read by the processor,
expressed in dB.
Common mode rejection ratio (CMRR) – The ratio of a device’s
differential voltage gain to common mode voltage gain. Expressed in dB,
CMRR is a comparative measure of a device’s ability to reject
interference caused by a voltage common to its terminal relative to
ground.
Common mode voltage – The voltage difference between the negative
terminal and analog common during normal differential operation.
Common mode voltage range – The largest voltage difference allowed
between either the positive or negative terminal and analog common
during normal differential operation.
Configuration word – Contains the channel configuration information
needed by the module to configure and operate each channel. Information
is written to the configuration word through the logic supplied in your
ladder program.
Cut-off frequency – The frequency at which the input signal is
attenuated 3 dB by the digital filter. Frequency components of the input
signal that are below the cut-off frequency are passed with under 3 dB of
attenuation for low-pass filters.
dB (decibel) – A logarithmic measure of the ratio of two signal levels.
Data scaling - The data format that you select to define the logical
increments of the channel data word.
Data word – A 16-bit integer that represents the value of the analog input
channel. The channel data word is valid only when the channel is enabled
and there are no channel errors.
Differential operation – The difference in voltage between a channel’s
positive and negative terminals.
Effective resolution – The number of bits in the channel data word that
do not vary due to noise.
Filter frequency – The user-selectable first-notch frequency for the A/D
converter’s digital filter. The digital filter provides high noise rejection at
the selected frequency.
Full-scale error (gain error) – The difference in slope between the
actual and ideal analog transfer functions.