Spectrum Controls 1746sc-INI4i, User Manual

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Chapter 5: Programming Examples 4-5
User’s Manual Pub. 0300266-04 Rev. A
Data Format
Selected
Input
Range
Actual Signal Limits Count Limits
Min.
Max. Min. Max.
0–20 mA 0 mA +20 mA 0 +16384
4–20 mA +4 mA +20 mA +3277 +16384
User-defined
scale A (and
B)
±10 V -10.25 V +10.25 V See note
➁ .
0–10 V -0.50 V +10.25 V
0–5 V -0.50 V +5.50 V
1–5 V +0.50 V +5.50 V
0–20 mA 0.0 mA +20.5 mA
4–20 mA +3.5 mA +20.5 mA
➀
Provides direct compatibility with the 1746-NI4 module.
➁ For user-defined scale A (or B ), the data in output words 4 and 5 (or 6 and 7)
determine the count limits. See the next subsection, Setting The User-Defined
Scale Limits, for information on the User-Defined Scale data format .
➂ Modules marked Series B Revision 1.00 or earlier had different signal limits
for the Scaled for PID data format (see the Owner’s Guide that came with your
module).
Open Input Circuit Response (configuration bits 7 and 8)
For 1–5 Vdc and 4–20 mA inputs only, use this bit field to define the state of the
channel data word when your module detects an open circuit for that channel:
• If you select zero on open input circuit, your module sets the channel data
word to zero during an open circuit condition.
• If you select max. on open input circuit, your module sets the channel data
word to its full-scale value during an open circuit.
•
If you select min. on open input circuit, your module sets the channel data
word to its low-scale value during an open circuit.
The full-scale and low-scale values (max. and min. count limits) are determined
by the channel’s data format and selected input range. See Table 4-2.
NOTE
IMPORTANT : If a circuit opens, your module provides input signal
values until it detects and flags the open circuit.
Input Filter Frequency (configuration bits 9 and 10)
Use this bit field to select one of four filters for a channel. The filter selected
affects the channel update time and noise rejection characteristics:
• A lower filter frequency increases the noise rejection and effective
resolution, but it also increases the channel update time.