Panametrics Sentinel LCT, Руководство пользователя

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Sentinel LNG User’s Manual 179
Chapter 7. HART Communications
7.6 Dynamic Variables
Only certain device variables can be published and are listed in Table 15 above. More publishable variables may be
added as the capabilities are added to the meter. Only the device variables listed in Table 15 may be assigned as
primary, secondary, tertiary or quaternary variables (PV, SV, TV and QV). Certain diagnostic variables have units
specific to that diagnostic. Refer to the Sentinel LNG for details on the use of diagnostic variables indicated by the
variable class specified as "Not Classified."
7.7 Status Information
7.7.1 Device Status
Bit 4 ("More Status Available") is set whenever any failure is detected. Command #48 furnishes specific information
about the failure. Refer to Section Error! Reference source not found., to the Sentinel LNG User’s Manual and to
Common Tables Specification Table 17. Due to the large number of device variables, the Non-Primary Variable Out of
Limits flag bit, Table 12, section 7.4.3 HCF_SPEC-99, is never set. Instead, monitor the Extended Device Status to
determine overall device variable status.
Bit 1 ("Non-Primary variable out of limits") is set only when any of the SV, TV or QV variables are out of their respective
limits. This bit is not set for variables not mapped to the SV, TV or QV.
7.7.2 Extended Device Status
Extended Device Code 0x01, Maintenance Required, is never set by the Sentinel LNG .
Code 0x02, Device Variable Alert, is set if the meter is in an alarm or warning state. Because of the complexity of
meter configuration and flow computation, the SEN898 may not set Device Variable Status indicators to identify
specific Device Variables as the cause of the alert. Refer to the manual for information about "flow" and "non-flow"
errors.