Rockwell Automation 1746-NT8 SLC 500 Thermocouple/mV Analog Input Module User Manual - Manual (Page 33)

Publication 1746-UM022B-EN-P - January 2005
Considerations Before Using Your Module 3-3
Chapter 4 provides detailed bit information about the data content of
the configuration word.
Input Image - Data Words and Status Words
Eight words of the SLC processor’s input image table are reserved for
the module. Input image words are multiplexed since each channel
has one data word and one status word. The corresponding
configuration word selects whether the channel status or channel data
is in the input image word.
Status bits for a particular channel reflect the configuration settings
that you entered into the configuration (output image) word for that
channel. To receive valid status, the channel must be enabled and the
module must have stored a valid configuration word for that channel.
Each input image word has a unique address based on the slot
number assigned to the module.
Example Address - To obtain the status/data word of channel 2
(input word 2) of the module located in slot 4 in the SLC chassis use
address I:4:2.
Chapter 4 provides detailed bit information about the content of the
data word and the status word.
Channel Filter Frequency
Selection The thermocouple module uses a digital filter that provides
high-frequency noise rejection for the input signals. The digital filter is
programmable, allowing you to select from four filter frequencies for
each channel. The digital filter provides the highest noise rejection at
the selected filter frequency. The graphs to follow show the input
channel frequency response for each filter frequency selection.
Selecting a low value (i.e. 10 Hz) for the channel filter frequency
provides the best noise rejection for a channel, but it also increases
the channel update time. Selecting a high value for the channel filter
frequency provides lower noise rejection, but decreases the channel
update time.
I:4.2
Slot
Word
Word
Delimiter
E lement
Delimiter
File Type