Method of operation
2
gas-net
C1 and C2
Page 2-3
arrival of an attention telegram
. You can also collect the most recent entry of a
standard query
. Finally, the processing of each individual query telegram can
be blocked. This function is useful if the associated DSfG station is temporarily
not in operation.
2.3 Foreign Protocols Module (for C2 devices only)
The
Foreign Protocols
module is incorporated in the C2 software only and fa-
cilitates the connection of several manufacturer-specific protocols (e.g. the Uni-
form protocol).
This functionality is intended for special applications; please contact Elster for
further information.
2.4 Simulating a gas quality entity via DSfG
(Gas quality simulation module)
The simulation of the gas quality data is a very special function of the
gas-net
DSfG Gateway. The DSfG regulations stipulate a specific process that
announces the existence of a new gas quality analysis across DSfG and dis-
tributes this analysis to all stations interested in it. However, if there is no gas
quality analyser incorporated in the gas measuring and regulating station, and
the gas quality data is injected via the telecontrol system, the gateway may
inject this remotely provided gas quality data in the DSfG bus as if it were a gas
2
According to the DSfG specifications the DSfG entities may generate attention telegrams
in case of special events. These attention telegrams are routed to all devices on the bus
as multi-address message.
3
A DSfG standard query serves to collect several coherent dates of a DSfG station at
once by querying with a single data element. For instance, via the “bia” data element you
address the standard query 1 of a volume corrector entity. The response to this query
supplies all current totalizers and important measurements. Other standard queries are
updated upon certain events. The standard query 2 (“bib”) for a volume corrector, for
example, is always updated at the end of an interval or at the beginning and end of
alarms. Each time such a data record is logged the ordinal number increases by one.
When polling via an ordinal number, such standard queries always supply exactly the data
record that belongs to the indicated ordinal number. The information on the highest ordinal
number ("level indicator") is also available via a DSfG data element. This way, you are in
the position to collect the most recent entry of a standard query via DSfG.
