Rockwell Automation 1771-IR , D17716.5.76 RTD INPUT MODULE - Manual (Page 32)

Module Status and Input Data
Chapter 6
6Ć2
Table 6.B
Bit/Word Description for RTD Input Module (1771-IR Series B)
Word Bit Definition
Word 1 Bits 00-05 Underrange indication for each channel; set when input is below the
normal operating range for copper or platinum RTD. Bit 00 for input 1,
bit 01 for input 2, etc. See Table 6.C.
Bit 06 Power-up bit is set when the module is alive but not yet configured.
Bit 07 EEPROM calibration values could not be read.
Bits 10-15 Overrange bits are set when the input is above the normal operating
range. Bit 10 for input 1, bit 11 for input 2, etc. See Table 6.C.
Bit 16 Real time sample time-out bit. See page 5-2.
Bit 17 Not used
Word 2 Bit 00-05 When set, indicates that default bias has been subtracted from the
input value. Only the remainder is shown in the data word. Each bit
relates to a single channel; bit 00 for input 1, etc. Default bias is
automatically applied when BCD formatted data cannot be displayed.
This will occur when measuring temperatures in Fahrenheit larger
than 999.9 degrees. The default bias value which is subtracted is
1000.0.
Bits 06-07 Not used
Bits 10-15 Sign bits for each channel. When set indicate that a certain input is
negative. Bit 10 corresponds to input 1, bit 11 to input 2, etc. These
bits are used for BCD and signed magnitude data formats.
Bits 16-17 Not used
Words 3-8 Input data words. The data words must be multiplied or divided by a
factor if whole numbers need to be displayed.
If you are reading temperature in o F or o C:
Then there is an implied decimal point (XXX.X) after the least
significant digit. Resolution is 0.1 o .
If you are reading resistance in milliohms (copper RTDs) (BTW word 1, bit 10 = 1):
Then there is an implied decimal point (XXX.XX).
If you are reading resistance in milliohms (all other RTDs) (BTW word 1, bit 10 = 0):
Multiply the data word by 30 to get the actual value in milliohms.
Resolution is 30 milliohms.
Word 9 Auto-calibration word.
Bit 00 Offset calibration complete
Bit 01 Gain calibration complete
Bit 02 Save complete
Bit 06 EEPROM fault