Allen-Bradley 1794-IRT8 User Manual

Publication 1794-6.5.12 - November 1997
4-4 Writing Configuration to and Reading Status from Your Module with a Remote I/O Adapter
Bit/Word Descriptions for the Thermocouple/RTD Input Module
(1794-IRT8) Block Transfer Read Words
8 Overrange Alarm Bits (channel 0 = bit 08, etc) Underrange Alarm Bits (channel 0 = bit 00, etc)
9 Flt Alm
Ch7
Flt Alm
Ch6
Flt Alm
Ch5
Flt Alm
Ch4
Flt Alm
Ch3
Flt Alm
Ch2
Flt Alm
Ch1
Flt Alm
Ch0
Rsvd
CJC 2
Alm
CJC 1
Alm
Rsvd Diagnostic Status
10 Resp
Flg
EDT command response EDT response data
Decimal 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
Octal 17 16 15 14 13 12 11 10 07 06 05 04 03 02 01 00
Word
Dec. Bits
(Octal Bits)
Description
Read Word 0 00-15 (00-17) Channel 0 Input data
Read Word 1 00-15 (00-17) Channel 1 Input data
Read Word 2 00-15 (00-17) Channel 2 Input data
Read Word 3 00-15 (00-17) Channel 3 Input data
Read Word 4 00-15 (00-17) Channel 4 Input data
Read Word 5 00-15 (00-17) Channel 5 Input data
Read Word 6 00-15 (00-17) Channel 6 Input data
Read Word 7 00-15 (00-17) Channel 7 Input data
Read Word 8 00-07 Underrange bits – these bits are set if the input signal is below the input channel’s minimum range.
Bit 00 corresponds to channel 0, bit 01 corresponds to channel 1, etc.
08-15 (10-17) Overrange bits – these bits are set if 1), the input signal is above the input channel’s maximum
range, or 2), an open detector is detected. Bit 08 (10) corresponds to channel 0, bit 09 (11)
corresponds to channel 1, etc.
Read Word 9 00-03 Diagnostic bits – represent module configuration and/or hardware errors.
Bit03020100
0000Reserved for factory use
0010Improper module configuration
0001 and 0011 thru 1111 Reserved for factory use
04 Not used.
05-06 Cold junction compensation alarm bits – These bits are set (1) when the corresponding cold
junction compensator lead is broken, unattached or shorted. Bit 05 corresponds to CJC1, and bit 06
to CJC2.
07 Not used
08-15 (10-17) Fault alarm bits – An alarm bit is set (1) when an individual input lead opens (broken,
disconnected). If the alarm is enabled, the channel reads maximum value. Bit 08 (10) corresponds to
input channel 0, bit 09 (11) to channel 1, etc.
Read Word 10 00-07 Extended data table command response data bits – These bits echo the EDT command data
written to the module during calibration.
08-14 (10-16) Extended data table command response bits – These bits echo the EDT command written to the
module during calibration.
15 (17) Reserved for factory use
Allen-Bradley PLCs

Allen-Bradley 1794-IRT8 Specifications

General

Manufacturer	Allen-Bradley
Product Type	FLEX I/O RTD Input Module
Input Type	RTD
Number of Inputs	8
Communication Interface	FLEX I/O
Resolution	16 bits
Isolation	1500 V AC
Operating Temperature	-40 to 70 °C (-40 to 158 °F)
Storage Temperature	-40 to 85 °C (-40 to 185 °F)
Relative Humidity	5 to 95% (non-condensing)
Isolation Voltage	1500 V AC
RTD Types	Pt100, Pt1000, Ni100, Ni120
Resistance Range	0…400 Ω
Certifications	CE
Voltage Category	Not Applicable