Emerson Daniel 3415

The gas composition includes the 21 standard components plus C6+ and Neopentane (see
for a list of data point names). Refer to for further information on how the GC-read gas
properties are mapped to the 'in-use' gas property data points.
The GC-read heating value and specific gravity are stored in the HeatingValueGC and
SpecificGravityGC data points, respectively.
Data polling
The meter periodically polls the GC looking for data updates. If the meter is
communicating normally with the GC, then it polls the GC every one minute looking for an
update (i.e., a change in the GC analysis time). Otherwise, the meter polls the GC every 15
seconds.
When the meter determines that a GC update is available for the specified stream number,
it then reads the GC data using multiple reads one second apart until all the data is read.
The GC analysis time is read again at the end of the data collection to determine if another
update occurred during the data collection (i.e., the data is not all from the same update).
If so, the meter discards the gas property data just read and begins looking immediately
for the next update.
If the meter cannot successfully communicate with the GC after four consecutive polls (15
seconds apart), then the meter indicates the communication alarm via the IsGCComErr
data point with the GCCommStatus data point indicating an error code (listed in Table 5-14
below).
GC Communications status listTable 5-14:
GCComm status value Error description
0 No error.
1 Desired stream not found.
2 GC controller is busy (error defined by Modbus protocol).
3 GC detected an illegal Modbus function code from the meter.
4 GC detected an illegal Modbus data address from the meter.
5 GC detected an illegal data value from the meter.
6 Failure in associated device (Modbus defined error).
7 GC has accepted the meter's request but is still processing.
8 A firmware logic error was detected.
9 Modbus address mismatch.
10 Modbus function code mismatch.
11 GC reports an exception code that is unrecognized.
12 The meter's Modbus request message is too long (exceeds the
maximum allowable length).
13 The GC's Modbus response message is too long (exceeds the
maximum allowable length).
14 GC response message has incorrect number of registers.
Configurations
Operations manual 73