Spectrum Controls 1769sc-HART Modules - Manual (Page 53)

Chapter 4: Module Data, Status, and Configuration
User's Manual 0300215-03 Rev. A
6-3
Input Data Not Valid Condition
The general status bits S0 to S3 also indicate whether or not the input data for a particular
channel, 0 through 3, 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 on page 9-4.
3.
If A/D hardware errors prevent the conversion process from taking place, the bit
condition is set (1).
6.3.4 Out of Service Status Bits OS0 to OS3 (Word 5)
Bits SO0 through SO3 of word 0 indicate whether the associated channel is out of service
(i.e. automatic HART acquisition is suspended).
Note: A channel that is placed out-of-service (i.e. Suspended) will automatically
resume service after three minutes, as long as no pass-through commands are issued
before the three minutes expires.
6.3.5 Over-Range Flag Bits O0 to O3 (Word 6)
Over-range bits for channels 0 through 3 are contained in word 6, 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.
Note: If a channel is configured for a voltage type input and an open-circuit condition
is present, the over-range flag bit will be set to indicate the open circuit condition and
the associated channel data word will display the full-scale value.
6.3.6 Under-Range Flag Bits U0 to U3 (Word 6)
Under-range bits for channels 0 through 3 are contained in word 6, 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 operating range for the represented channel or
sensor. The module automatically resets (0) the bit when the under-range condition is
cleared and the data value is within the normal operating range.
Note: If a channel is configured for a current type input and an open-circuit condition
is present, the under-range flag bit will be set to indicate the open circuit condition and
the associated channel data word will display the minimum scale value.
6.3.7 High Process Alarm Flag Bits H0 to H3 (Word 6)
The high process alarm flag is set when the measured analog signal exceeds the high
process alarm setpoint. The high process alarm setpoint is defined in Section 6.4 Module
Configuration.