Rockwell Automation 1762-IR4 RTD/Resistance Input Module - Manual (Page 91)

1 Publication 1762-UM003A-EN-P - February 2003
Glossary
The following terms and abbreviations are used throughout this
manual. For definitions of terms not listed here refer to Allen-Bradley’s
Industrial Automation Glossary, Publication AG-7.1.
A/D Converter
Refers to the analog to digital converter inherent to the module. The
converter produces a digital value whose magnitude is proportional to
the magnitude of an analog input signal.
attenuation
The reduction in the magnitude of a signal as it passes through a
system.
bus connector
A 16-pin male and female connector that provides electrical
interconnection between the modules.
channel
Refers to input interfaces available on the module’s terminal block.
Each channel is configured for connection to a thermocouple or
millivolt input device, and has its own data and diagnostic status
words.
channel update time
The time required for the module to sample and convert the input
signals of one enabled input channel and update the channel data
word.
common mode rejection
For analog inputs, 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 (CMMR)
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 input terminals relative to ground. CMRR=20 Log10 (V1/V2)
common mode voltage
The voltage difference between the negative terminal and analog
common during normal differential operation.