Spectrum Controls 1756sc-IF8u - Manual (Page 6)

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ControlLogix ™ Universal Analog Input Modules
1756 Series ControlLogix Module Installation Instructions
(Each module has separate document for installation)
1756-5.5,
-5.42
1756-L1, Logix5550 Controller User Manual 1756-6.5.12
-L1M1, -L1M2
1756-DHRIO ControlLogix Data Highway Plus
Communication Interface Module User Manual
1756-6.5.2
1756-ENET ControlLogix Ethernet Communication Interface
Module User Manual
1756-6.5.1
To obtain a copy of any of the Allen-Bradley documents listed, contact
your local Allen-Bradley office or distributor.
Terms &
Abbreviations You
Should Know
You should understand the following terms and abbreviations before using
this guide.
A/D - Refers to analog-to-digital conversion. The conversion produces a
digital value whose magnitude is proportional to the instantaneous
magnitude of an analog input signal.
Attenuation – The reduction in magnitude of a signal as it passes through
a system. The opposite of gain.
Channel – Refers to one of eight, small-signal analog input interfaces to
the module’s terminal block. Each channel is configured for connection to
a input device, and has its own configuration and status words.
Chassis – See rack.
CJC - (Cold Junction Compensation) The means by which the module
compensates for the offset voltage error introduced by the temperature at
the junction between the thermocouple lead wire and the input terminal
block (the cold junction).
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.