Chapter 5
Channel Configuration, Data, and Status
5–13
Table 5.N
Bit Descriptions for Temperature Units Selection
Binary
Value
Select
If you want to
0
degrees Celsius
display the channel data word in degrees Celsius.
1
degrees Fahrenheit
display the channel data word in degrees Fahrenheit.
Filter Frequency Selection (Bits 9 and 10)
Table 5.O shows the descriptions for 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 (refer to chapter 4 for details).
Table 5.O
Bit Descriptions for Filter Frequency Selection
Binary
Value
Select
Description
00
10 Hz
provide both 50 Hz and 60 Hz AC line noise filtering. This setting increases the
channel update time, but also increases the noise rejection.
01
50 Hz
provide 50 Hz AC line noise filtering.
10
60 Hz
provide 60 Hz AC line noise filtering.
11
250 Hz
provide 250 Hz AC noise filtering. This setting decreases the noise rejection,
but also decreases the channel update time.
Channel Enable Selection (Bit 11)
Table 5.P shows the description for bit 11. You use the channel enable bit to
enable a channel. The RTD module only scans those channels that are
enabled. To optimize module operation and minimize throughput times, you
should disable unused channels by setting the channel enable bit to zero.
When set (1), the channel enable bit is used by the module to read the
configuration word information you have selected. While the enable bit is
set, modification of the configuration word may lengthen the module update
time for one cycle. If any change is made to the configuration word, the
change must be reflected in the status word before new data is valid. (Refer
to Channel Status Checking on page 5–19.)
While the channel enable bit is cleared (0), the channel data word and status
word values are cleared. After the channel enable bit is set, the channel data
word and status word remain cleared until the RTD module sets the channel
status bit (bit 11) in the channel status word.
Summary of Contents for SLC 500 1746-NR4
Page 1: ...User Manual SLC 500t RTD Resistance Input Module Cat No 1746 NR4 Allen Bradley AB Spares ...
Page 15: ...Preface P 8 Notes AB Spares ...
Page 37: ...Chapter 2 Quick Start 2 12 Notes AB Spares ...
Page 63: ...Chapter 4 Preliminary Operating Considerations 4 12 Notes AB Spares ...
Page 87: ...Chapter 5 Channel Configuration Data and Status 5 24 Notes AB Spares ...
Page 107: ...Chapter 7 Module Diagnostics and Troubleshooting 7 8 Notes AB Spares ...
Page 117: ...Chapter 8 Application Examples 8 10 Notes AB Spares ...
Page 123: ...Appendix A Specifications A 6 Notes AB Spares ...
Page 125: ...Appendix B RTD Standards B 2 Notes AB Spares ...
