Spectrum Controls 1746sc-NI8u User Manual
Page 60
48
SLC 500
™
Universal Analog Input Module
Important: If the channel for which you are seeking status is disabled,
all bit fields are cleared. The status word for any disabled
channel is always 0000 0000 0000 0000 regardless of any
previous setting that may have been made to the
configuration word.
Explanations of the status conditions follow.
Channel Status (Bit 0)
The channel status bit indicates operational state of the channel. When
the channel enable bit is set in the configuration word (bit 0), the universal
module configures the selected channel and takes a data sample for the
channel data word before setting this bit in the status word.
Input Type Status (Bits 1-5)
The input type bit field indicates what type of input signal you have
configured for the channel. This field reflects the input type defined in the
channel configuration word.
Data Format Type Status (Bits 6 and 7)
The data format bit field indicates the data format you have defined for
the channel. This field reflects the data type selected in bits 6 and 7 of the
channel configuration word.
Open Circuit Type Status (Bits 8 and 9)
The open-circuit bit field indicates how you have defined the open circuit
bits configuration word, and therefore, the response of the universal
module to an open-circuit condition. This feature does not apply to the 0-5
V, 1-5 V, 0-10 V, ±2 V, ±10 V, or 0-20mA input ranges, and a properly
configured channel of those types will give the disabled status. It applies
to all others, including CJC temperature input.
Channel Filter Frequency (Bits 10 and 11)
The channel filter frequency bit field reflects the filter frequency you
selected in the configuration word.
Open Circuit Error (Bit 12)
This bit is set (1) whenever a configured channel detects an open-circuit
condition at its input. Short circuited RTD inputs will also flag this error
condition. A short circuit for RTDs exist when the module reads less than
3 ohms across the RTD input. An open-circuit at the CJC sensor will also
flag this error if the channel input type is either thermocouple or CJC
temperature. A range error on the CJC sensor will also flag this bit if the
input type is a thermocouple type.