Rockwell Automation 1746-NT8 SLC 500 Thermocouple/mV Analog Input Module User Manual - Manual (Page 105)

Publication 1746-UM022B-EN-P - January 2005
Glossary 3
Input data scaling
Depends on the data format that you select for the channel data word.
You can select from scaled-for-PID or Engineering Units for millivolt,
thermocouple, or CJC inputs, which you must compute to fit your
application’s temperature or voltage resolution.
Local system
A control system with I/O chassis within several feet of the processor,
and using 1746-C7 or 1746-C9 ribbon cable for communication.
LSB (least significant bit)
The bit that represents the smallest value within a string of bits. The
“weight” of this value is defined as the full-scale range divided by the
resolution.
Multiplexer
A switching system that allows several input signals to share a
common A/D converter.
Normal mode rejection (differential mode rejection)
A logarithmic measure, in dB, of a device’s ability to reject noise
signals between or among circuit signal conductors, but not between
the equipment grounding conductor or signal reference structure and
the signal conductors.
Remote system
A control system where the chassis can be located several thousand
feet from the processor chassis. Chassis communication is via the
1747-SN Scanner and 1747-ASB Remote I/O Adapter.
Resolution
The smallest detectable change in a measurement, typically expressed
in engineering units (e.g. 0.15×C) or as number of bits. For example, a
12-bit value has 4,096 possible counts. It can therefore be used to
measure 1 part in 4096.
Sampling time
The time required by the A/D converter to sample an input channel.