Spectrum Controls 1769sc-IF8u - Manual (Page 45)

Chapter 4: Module Data, Status, and Configuration 35
Input Data Not Valid Condition
The general status bits S0 to S7 also indicate whether or not the input data
for a particular channel, 0 through 7, is being properly converted (valid) by
the module. This “invalid data” condition can occur (bit set) when the
download of a new configuration to a channel is accepted by the module
(proper configuration) but before the A/D converter can provide valid
(properly configured) data to the 1769 bus master/controller. The following
information highlights the bit operation of the Data Not Valid condition.
1. The default and module power-up bit condition is reset (0).
2. The bit condition is set (1) when a new configuration is received and
determined valid by the module. The set (1) bit condition remains until
the module begins converting analog data for the previously accepted
new configuration. When conversion begins, the bit condition is reset
(0). The amount of time it takes for the module to begin the conversion
process depends on the number of channels being configured and the
amount of configuration data downloaded by the controller.
NOTE: If the new configuration is invalid, the bit function remains reset
(0) and the module posts a configuration error. See Configuration Errors in
chapter 5.
3. If A/D hardware errors prevent the conversion process from taking
place, the bit condition is set (1).
Open-Circuit Flag Bits (OC0 to OC7)
Bits OC0 through OC7 of word 8 contain open-circuit error information
for channels 0 through 7, respectively. Errors for the CJC sensor are
indicated by OC8 of word 10. The bit is set (1) when an open-circuit
condition exists.
Note: Open circuit detection is applied once every module scan if enabled.
See Open-Circuit Detection in chapter 5 for more information on open-
circuit operation.
Over-Range Flag Bits (O0 to O7) Over-range bits for channels 0
through 7 are contained in word 9, even-numbered bits. They apply to all
input types. When set (1), the over-range flag bit indicates an input signal
that is at the maximum of its normal operating range for the represented
channel or sensor. The module automatically resets (0) the bit when the
data value falls below the maximum for that range. The Over-range bit for
the CJC sensor is contained in word 10, bit 14.
Under-Range Flag Bits (U0 - U7)
Under-range bits for channels 0 through 7 are contained in word 9, odd-
numbered bits. They apply to all input types. When set (1), the under-
range flag bit indicates an input signal that is at the minimum of its normal