Rockwell Automation 1790P-4R0 CompactBlock LDX I/O RTD/Resistance Input Module - Manual (Page 35)

Publication 1790-UM002A-EN-P
Module Data, Status, and Channel Configuration for DeviceNet 3-5
Common mode noise rejection for the module is better than 110 dB at 50
Hz (50 Hz filter) and 60 Hz (60 Hz filter). The module performs well in
the presence of common mode noise. Improper earth ground can be a
source of common mode noise.
Channel Step Response Another module characteristic determined by filter frequency is channel
step response, as shown in the following table. The step response is the
time required for the analog input signal to reach 100 percent of its
expected final value, given a full-scale step change in the input signal.
Thus, if an input signal changes faster than the channel step response, a
portion of that signal will be attenuated by the channel filter. The channel
step response is calculated by a settling time of 3 x (1 / filter frequency).
NOTE
Transducer power supply noise, transducer circuit noise,
and process variable irregularities can also be sources of
common mode noise.
Table 3.5 Filter Frequency vs. Channel Step Response
Filter Frequency Step Response
10 Hz 300 ms
25 Hz 120 ms
50 Hz 60 ms
60 Hz 50 ms
100 Hz 30 ms
250 Hz 12 ms
500 Hz 6 ms