Rockwell Automation 1746-NT8 SLC 500 Thermocouple/mV Analog Input Module User Manual - Manual (Page 42)

Publication 1746-UM022B-EN-P - January 2005
4-2 Channel Configuration, Data, and Status
The configuration word default settings are all zero. Next, we describe
how you set configuration bits of a channel configuration word to set
up the following channel parameters:
•
data format such as engineering units, counts, or scaled-for-PID
•
how the channel should respond to a detected open-input
circuit
•
filter frequency selection
•
temperature units in °C or °F
•
whether the channel is enabled or disabled
•
whether status or data information is selected for the module’s
input image table
Channel Configuration
Procedure The channel configuration word consists of bit fields, the settings of
which determine how the channel operates. This procedure looks at
each bit field separately and helps configure a channel for operation.
Refer to the chart on page 4-4 and the bit field descriptions that follow
for complete configuration information.
1. Determine which channels are used in your program and enable
them. Place a one in bit 0 if the channel is to be enabled. Place
a zero in bit 0 if the channel is to be disabled.
2. Determine the input device type (J, K, etc. thermocouple) (or
mV) for a channel and enter its respective four-digit binary code
in bit field 1 through 4 of the channel configuration word.
3. Select a data format for the data word. Your selection determines
how the analog input value from the A/D converter will be
expressed in the data word. Enter your two-digit binary code in
bit field 5 and 6 of the channel configuration word.
4. Determine the desired state for the channel data word if an
open-circuit condition is enabled and detected for that channel.
Enter the two-digit binary code in bit field 7 and 8 of the
channel configuration word.
TIP
When using RSLogix 500 version 6.10 or higher, you
can use the software’s I/O wizard to configure the
NT8 channels. Refer to Appendix C for more
information.