2
Method of operation
gas-net
C1 and C2
Page 2-6
course of time. The original totalizer is thus not just automatically transferred to
the created totalizer. This is important because a possible running backwards of
the intercalated totalizer must be prevented.
An intercalated totalizer will fluctuate around the original totalizer when the flow
rates are changing. In principle, this totalizer can only represent an approximate
value, which is the more precise the lower the flow rate fluctuations are and the
more often a new intercalation value comes in.
The procedure is only started anew if an error occurs, such as a mains failure,
an error of the totalizer input value or an exceeding of the parameterizable
communication timeout. As soon as the error is no longer pending, the newly
supplied totalizer will be transferred to the intercalated totalizer and the creation
of the intercalated totalizer will be restarted.
There is a special procedure for recognizing the setting of a totalizer: A maxi-
mum flow rate Qmax is parameterized that must not be exceeded. An implausi-
ble totalizer increment violating the defined maximum flow rate is interpreted as
“setting”. In such a case, too, the new totalizer will be immediately transferred to
the intercalated totalizer and the creation of the intercalated totalizer will be
started anew.
Furthermore, the intercalation of the intercalated counters is stopped below a
flow rate of 1/10 of the maximum flow rate. In such a case only the totalizers
being supplied via the protocol will be transferred to the intercalated totalizer.
This prevents that the intercalated totalizer reading is higher than the original
totalizer when the station is shut.
2.5.3 Totalizing
Counters
A totalizing counter totalizes up to 10 counters and creates a total count value.
Each of the involved counters may be included in the totalizing counter with a
positive or negative sign. If all involved counters have a flow rate input value, a
total flow rate is additionally created.
A totalizing counter is considered being
disturbed
if at least one of the involved
counters is disturbed.
If a counter with a negative sign influences a totalizing counter, the overall result
should always be positive. Nevertheless, it may happen from time to time that, in
terms of figures, a negative total increment occurs – for instance, in case of
pulse inputs with different input types (HF, LF). A totalizing counter never counts
backwards. An internal buffer retains negative quantities instead. The retained
