Rockwell Automation 1769-IF4XOF2 Compact 8-Bit Low Resolution Analog I/O Combination Module - Manual (Page 56)

Publication 1769-UM008A-EN-P - November 2001
4-12 1769-IF4XOF2 Module Data, Status, and Configuration Channels
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Fault Value (Channel 0 and 1) – Words 2 and 4 allow you to
enter the integer values that output Channel 0 (Word 2) and
output Channel 1 (Word 4) should assume when the system
transitions to the Fault mode. The value must be in increments
of 128 (0, 128, 256, etc.) for proper operation. If the value
entered is outside the acceptable increment or range, the
module generates a configuration error for that channel. The
module default value is zero.
Input Filter Selection
The 1769-IF4XOF2 has a fixed input filter. No configuration is
required.
Channel Step Response
The module’s fixed filter frequency determines the channel’s step
response. The step response is the time required for the analog input
signal to reach 63% or 90% of its expected final value. This means that
if an input signal changes faster than the channel step response, a
portion of that signal will be attenuated by the channel filter.
Channel Cut-Off Frequency
The -3 dB frequency is the filter cut-off frequency. The cut-off
frequency is defined as the point on the input channel frequency
response curve where the frequency components of the input signal
are passed with 3 dB of attenuation. All input frequency components
at or below the cut-off frequency are passed by the digital filter with
less than 3 dB of attenuation. All frequency components above the
cut-off frequency are increasingly attenuated.
IMPORTANT
PMx, FMx, PFEx, Channel x Program (Idle) Value,
and Channel x Fault Value functions are not
supported by all controllers. Refer to your controller’s
user manual for details.
Table 4.7 Filter Frequency and Step Response
Fixed Filter Frequency Filter Cut-Off Frequency Step Response
% Complete
Step Response
Time
2.7 kHz 2.7 kHz 63% 59 us
2.7 kHz 2.7 kHz 90% 136 us (Nominal)