Panametrics Sentinel LCT, User Manual

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Sentinel LNG User’s Manual 187
Chapter 7. HART Communications
7.12.4 Self-Test
The meter responds to the self-test request, but performs no additional diagnostic functions. (The meter tests for
errors and reports them after each measurement cycle.) Support for command 41 is included to facilitate future
implementation.
7.12.5 Command Response Delay
7.12.6 Busy and Delayed Response
The Sentinel LNG never transmits a busy response code when replying to a command. The delayed response
mechanism is not implemented.
7.12.7 Long Messages
The data field in Command 21, Read Unique Identifier Associated with Long Tag, is the largest that the Sentinel LNG
will receive. The message contains 32 characters (bytes). The reply to Command 21 contains the largest data field
sent by the Sentinel LNG , 18 bytes (including the two status bytes).
7.12.8 Non-Volatile Memory
The meter uses nonvolatile memory to store the configuration parameters. Flow totals are also periodically cached
to preserve data in case power is interrupted.
7.12.9 Operating Modes
Fixed current mode is implemented using Command 40. This mode is cleared by power loss or reset.
7.12.10 Write Protection
The meter contains two write protect switches.
7.12.11 Write Protect Switch
The write protect switch activates the write protect mode and will generate "In Write Protect" response when active.
An LED will be lit when the write protect switch is active.
7.12.12 Totals Protect Switch
The Totals Protect switch is used to ensure conformity to the Measuring Instruments Directive (MID). The meter totals
cannot be reset when the meter is restricted via the Totals Protect switch. An LED is lit when the Totals Protect Switch
is active.
7.13 Capability Checklist
Minimum 1ms
Typical 20ms
Maximum 256ms
Manufacturer, model and revision GE Sensing Sentinel LNG flowmeter, Rev. 1.0
Device type Transmitter
HART revision 6.3
Device Description available No
Number and type of sensors
1 to 4 pairs of acoustic transducers,
0 to 4 temperature or pressure sensors (for
flow correction)
Number and type of actuators 0
Number and type of host side signals One 4-20mA analog output,
two optional frequency/totalizer outputs
Number of Device Variables 240
Number of Dynamic Variables 4