Rockwell Automation 1771-IR Series D RTD Input Module User Manual - Manual (Page 46)

6–8 Calibrating Your Module
Publication 1771Ć6.5.129 - March 2000
Table 6.A
Value for Bits 7 through 0
Bit Value
Bit 07 Sign bit
Bit 06 = 0.0976562%
Bit 05 = 0.0488281%
Bit 04 = 0.024414%
Bit 03 = 0.012207%
Bit 02 = 0.00610351%
Bit 01 = 0.00305175%
Bit 00 = 0.00152587%
You use the values that most nearly add up to the percentage that you
determined in step 8. For example, to attain the value of 0.0597%,
you need to add:
Percentage Bit Number
0.0488281 Bit 05
0.00610351 Bit 02
0.00305175 Bit 01
0.00152587 Bit 00
Total = 0.0595%
As you can see, 0.0595 is smaller than 0.0597, but this value is as
close as you can come using the 7 possible values listed in Table 6.A.
You would enter 10100111 in the lower byte of word 9. This sets bits
05, 02, 01 and 00, which subtracts a gain correction of 0.0595% from
the actual input data value.
Important: When you enter data in the least significant byte,
remember to reenter the data in the most significant
byte in the word. If you don’t, the data in the MSB is
lost.
4. Repeat above steps for channels 2 through 6.
5. Apply the values by sending a BTW to the module.
In this chapter, you learned how to calibrate your input module.
Chapter Summary