Rockwell Automation 1756-XXXX ControlLogix Analog I/O Modules - Manual (Page 364)

364 Publication 1756-UM009C-EN-P - December 2010
Appendix E Additional Specification Information
Because the specifications listed in Appendix A include a typical and worst case
PPM/ °C for each module, you can determine multiple Gain Drift with
Temperature values for each module.
Module Error Over Full Temperature Range
The Module Error Over Full Temperature Range specification represents the
error that occurs if the module’s ambient temperature changes a total of
60 °C (that is, from 0…60 °C (0…140 °F) or 60…0 °C). While this
temperature change is extremely unlikely, it represents the worst case scenario.
This specification is determined by multiplying the temperature change by the
maximum Gain Drift with Temperature for the given module. In other words,
we determine Module Error Over Full Temperature Range with the
following formula:
Module Error Over Full Temperature = Full Temperature Range x Gain Drift
with Temperature
EXAMPLE
For example, the 1756-IT6I module has a maximum Gain Drift
with Temperature specification of 80 ppm/ °C. The 80 ppm
represents 0.008% of the module’s full operating temperature.
If the module was calibrated to operate in the -12…78mV input
range, then following formula is used:
(0.008/ °C) x 90 mV = +/-7.2 µV/ °C
For every degree Celsius that the module’s operating
temperature moves from the calibration temperature, the
maximum calibration accuracy deviation is +/-7.2 µV.
EXAMPLE
The 1756-IT6I module has a maximum Gain Drift with
Temperature specification = 80 ppm/ °C.
Module Error over Full Temperature Range = 60 °C (full
temperature range) X 80 ppm/ °C (gain drift). The result is
4800 ppm or 0.48%.