Spectrum Controls 1746sc-NI8u - Manual (Page 47)

Chapter 4: Channel Configuration, Data, and Status 35
input types. Check table 11 to make sure you selected a valid
combination.
4. Determine the desired state for the channel data word if an open circuit
condition is enabled and detected for that channel. Enter the 2-digit
binary code in bit field 8-9 of the channel configuration word. Not all
input types support open circuit detection. Review the “Open Circuit
State” description on page 43 to verify applicability.
5. If the channel is configured for thermocouple inputs, RTD or the CJC
sensor, determine if you want the channel data word to read in degrees
Fahrenheit or degrees Celsius and enter a one or a zero in bit 10 of the
configuration word. If the channel is configured for a mV, V, mA, or
resistance analog sensor, enter a zero in bit 9.
6. Determine the desired input filter frequency for the channel and enter
the 2-digit binary code in bit field 11-12 of the channel configuration
word. A lower filter frequency increases the channel update time, but
also increases the noise rejection and channel resolution. A higher
filter frequency decreases the channel update time, but also decreases
the noise rejection and effective resolution.
7. If an RTD or resistance input type was selected, enter the digit binary
code corresponding to 2- or 4-wire, or 3-wire, RTD inputs in bit 13. If
a thermocouple, mV, V, or mA type is used, enter a 0 in bit 13.
8. If auto-calibration is desired, place a zero in bit 14. If auto-calibration
is not desired, place a one in bit 14.
9. Determine whether the channel input image word should contain data
or status. Place a one in bit 15 if channel data is desired. Place a zero
in bit 15 if status is desired.
10. Build the channel configuration word for every channel on each
universal module repeating the procedures given in steps
1-9.
11.Enter this configuration into your ladder program and copy it to the
universal module.
Each channel has a word in the module’s output image which determines
the way that channel functions. Channels 0 through 3 may be configured
for current, voltage or thermocouple input types. No RTD or resistance
input types are allowed on those channels. Channels 4 through 7 may be
configured for current, voltage, thermocouple, RTD or resistance inputs.
The definition of the bits in the configuration words are described in the
charts below.