Rockwell Automation 1771-IR Series D RTD Input Module User Manual - Manual (Page 11)

Chapter
1
Publication 1771Ć6.5.129 - March 2000
Overview of the RTD Input
Module
This chapter gives you information on:
•
features of the input module
•
how an input module communicates with programmable
controllers
The RTD input module is an intelligent block transfer module that
interfaces analog input signals with any Allen–Bradley
programmable controllers that have block transfer capability. Block
transfer programming moves input data words from the module’s
memory to a designated area in the processor data table in a single
scan. It also moves configuration words from the processor data
table to module memory.
The input module is a single slot module and requires no external
power supply. After scanning the analog inputs, the input data is
converted to a specified data type in a digital format to be transferred
to the processor’s data table on request. The block transfer mode is
disabled until this input scan is complete. Consequently, the
minimum interval between block transfer reads (50ms) is the same as
the total input update time for each analog input module.
The RTD input module senses up to 6 RTD signals at its inputs and
converts them to corresponding temperature or resistance in 4–digit
BCD or 16–bit binary format.
Module features include:
•
Six resistance temperature detector inputs
•
Reports o C, o F, or ohms for 100 ohm platinum or 10 ohm copper
sensors
•
Reports ohms for other types of sensors
•
software configurable
•
0.1 degree/10 milliohm input resolution
•
auto–calibration
•
open wire detection
The module can be configured for 100 ohm platinum or 10 ohm
copper RTDs, or other sensor types such as 120 ohm nickel RTDs.
Temperature ranges are available in degrees C or F. Values can also
be measured in ohms.
Chapter Objectives
Module Description
Features of the Input
Module