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228 Hardware configuration
Section 6: Meter operation Reference, Installation, and Operations Manual
June 2013 3-9000-743 Rev S
6.5.1 Hardware configuration
The Daniel Mark III Ultrasonic Gas Flow Meter communicates serially with the Daniel GC using
Option Board Port C in either RS-232 or RS-485 (half duplex) mode. Refer to “Port C Driver
Configuration” in Section 3.5.1 for further information on connecting the two devices.
6.5.2 Software configuration
It is recommended that the Daniel MeterLink Field Setup Wizard be used to configure the GC
interface (see Section 5.6.13).
The GasPropertiesSrcSel data point is used to select whether the gas property data is live (read
from a GC) or fixed. The GCSerialPort data point is used to either disable the GC interface or
select (Option Board) Port C for communicating with the GC. These two points are
automatically set via the Daniel MeterLink
Field Setup Wizard.
The following information is required in order to configure the Daniel Mark III Ultrasonic Gas
Flow Meter to interface with a GC:
• the GC Modbus communication configuration:
–
protocol (GCProtocol)
– baud rate (GCBaud)
– Modbus address (GCModbusID)
• the desired stream number (GCStreamNumber) and the length of time to wait for the
desired stream number (GCDesiredStreamTimeout), and
• heating value configuration:
–
type of heating value (GCHeatingValueType)
– unit (GCHeatingValueUnit)
The software configuration also allows for the selection of how the meter is to respond when
the GC-read data is considered invalid (GasPropertiesSrcSelGCAlarm): whether to ‘freeze’ the
‘in-use’ gas property data to the last good GC-read data or to use fixed gas property data
instead.
The length of time to wait for the desired stream (GCDesiredStreamTimeout) is not
configurable within the Daniel MeterLink
Field Setup Wizard. It is, however, configurable using
the Daniel MeterLink
Edit/Compare Configuration utility. Its default value is 100 minutes and
limits are [6, 255 min]. The total number of streams and the update time per stream should be
taken into account when updating this parameter.
6.5.3 Gas property data
The gas property data read from the GC includes gas composition, heating value, and specific
gravity (relative density).
The gas composition includes the 21 standard components plus C
6
+ and Neopentane (see
Tab le 6 -8 for a list of data point names). Refer to Section 6.1.16 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 Specific-
GravityGC data points, respectively.