Cyclic Lead Compensation (Bit 4); Selecting Input Filter Frequency (Bits 0 Through 2) - Spectrum Controls 1769 User Manual

4-6 Compact™ IO Isolated RTD/Resistance Module
Input
Filter
4.17
Hz
10.0
Hz
16.7
Hz
6
Not all controllers allow online configuration changes. Refer to your controller's user manual for details. During
an online configuration change, input data for that channel is not updated by the module.
7
If lead compensation is enabled, use this column for channel update times.
User's Manual Pub. 0300241-01 Rev. A
Table 4-4 (Open-Circuit Response)
Response Definition
Option
Upscale Sets the input data value to full upper scale value of channel data word.
The full-scale value is determined by the selected input type and data
format.
Downscale Sets the input data value to full lower scale value of channel data word.
The low scale value is determined by the selected input type and data
format.
Last State Sets the input data value to the last input value prior to the detection of
the open-circuit.
Zero Sets the input data value to 0 to force the channel data word to 0.

4.2.8 Cyclic Lead Compensation (Bit 4)

For each channel, the module measures lead resistance in one of two ways. Set bit 4 to 0
to enable measurement and compensation of lead resistance every 6 module scans. One
channel is measured per module update to limit the impact to channel throughput. You
can also implement a lead wire calibration cycle any time, at your command, by enabling
and then disabling this bit in your control program.
wire compensation occurs automatically on a system mode change from Program-to-Run
or if any online configuration change is made to a channel.

4.2.9 Selecting Input Filter Frequency (Bits 0 through 2)

The input filter selection field allows you to select the filter frequency for each channel 0
through 5. The filter frequency affects the following, as explained later in this chapter:
•
Noise rejection characteristics for module inputs
•
Cut-Off Frequency
•
Repeatability
•
Module update time
The table below summarizes the effects of each filter selection.
Table 4-6 (Filter Effects)
Channel Channel
Update Update
Time Time
Lead Lead
Compensation Compensation
Disabled Enabled
242 msec 964 msec
102 msec 404 msec
62 msec 244 msec
6
Regardless of the state of bit 4, lead
Cut-Off
7
Frequency Repeatability
1 Hz See Appendix
A
2 Hz See Appendix
A
4 Hz 2x(4.17 Hz
values)
From Appendix
A
NMRR NMRR
50 Hz 60 Hz
Rejection Rejection
74 dB 74 dB
70 dB 70 dB
65 dB NA