Rockwell Automation 1746-NT4 Series B,D17466.6.1 SLC 500 4-Channel Thermocouple/mV Input Module User Manual - Manual (Page 63)

Publication 1746-UM007C-EN-P - July 2004
Channel Configuration, Data, and Status 5-11
Select Temperature Units (Bit 8)
The temperature units bit lets you select temperature engineering
units for thermocouple and CJC input types. Units are either degrees
Celsius (°C) or degrees Fahrenheit (°F). This bit field is only active for
thermocouple and CJC input types. It is ignored when millivolt inputs
types are selected.
Select Channel Filter Frequency (Bits 9 and 10)
The channel filter frequency bit field lets you select one of four filters
available for a channel. The filter frequency affects the channel update
time and noise rejection characteristics. A smaller filter frequency
increases the channel update time, but also increases the noise
rejection and channel resolution. A larger filter frequency decreases
the noise rejection, but also decreases the channel update time and
channel resolution.
•
250 Hz setting provides minimal noise filtering.
•
60 Hz setting provides 60 Hz AC line noise filtering.
•
50 Hz setting provides 50 Hz AC line noise filtering.
•
10 Hz setting provides both 50 Hz and 60 Hz AC line noise
filtering.
When a CJC input type is selected, this field is ignored.
IMPORTANT
If you use engineering units (1 mode) and
Fahrenheit temperature units (i.e. 0.1°F), the full
scale temperature for thermocouple type B is not
achievable with 15-bit numerical representation. An
over range error will occur for that channel if it tries
to represent the full scale value. The maximum
representable temperature is 3276.7°F (instead of
3308°F).