Spectrum Controls 1746sc-INI4i, User Manual

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4-6 Chapter 4: Using Your Input Module
User’s Manual Pub. 0300128-04 Rev. A
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A higher filter frequency decreases the update time, but it also decreases the
noise rejection and effective resolution.
Refer to Chapter 3, Items To Consider Before Using Your Module, for more
information on selecting a filter frequency.
Auto-Calibration Enable (configuration bit 11)
Use this bit to enable or disable auto-calibration. When enabled, auto- calibration
occurs every 10 seconds. Auto-calibration also occurs whenever you configure a
channel (regardless of the setting of this bit).
Unused Bits (configuration bits 12–15)
These bits are not defined. To prevent a configuration error, ensure that bits 12
through 15 are set to zero.
Section 4.3
Setting The User-
Defined Scale Limits
(optional)
For special applications (such as when using a sensor with a non-standard
operating range), the 1746sc-INI4i and 1746sc-INI4vi input modules let you
define up to two custom data formats. These “user-defined scales” are very
similar to the “proportional counts” data format provided by your module and
many Allen-Bradley modules—except that instead of scaling the input signal to a
previously defined range (-32,768 to +32,767), your module can scale the input
signal to a range defined by the values in output words 4 and 5 (for user-defined
scale A) or output words 6 and 7 (for user-defined scale B).
NOTE
After setting user-defined scale limits, you must toggle the channel enable
bit (configuration bit 0) in order for your module to use the new limits.
Output word 4 (or 6) defines the low limit of the user-defined scale (down to -
32768), while output word 5 (or 7) defines the high limit of the user-defined
scale (up to +32767). The high limit value must be greater than the low limit
value for proper operation.
You select the data format for each channel using that channel’s configuration
word, explained earlier in this chapter in Configuring Each Input Channel.