12
We reserve the right to make changes without notice
H 355 - IET 7143 - 7183 C1 Eng.
18.01.10 AM
Rev. 06
COSTER
17.
6
Calculation of flow of vector fluid and of instantaneous power
On the basis of the signal received from the volumetric meters the instantaneous flow in m
3
/h is calculated and also
the instantaneous power in Kw which at that moment is being supplied to the site.
17.
7
Recording of the meter readings
The recording of the meter readings is carried out so as to ensure there is absolutely no loss of data.
When the meter is being used to its maximum capacity the four most important meter readings to be recorded are:
– ENERGY HEATING SIDE (MWh)
– VOLUME HEATING SIDE (m
3
)
– ENERGY COOLING SIDE (MWh)
– VOLUME COOLING SIDE (m
3
)
All the four meter readings are also recorded as “Total meter readings”: these are four additional values which
represent the sum of meter readings from when the meter was first used; they can be compared to the total mileage
of an automobile.
The total meter readings cannot be altered in any way since they represent values which regard important fiscal
matters.
The meter readings normally displayed can be adjusted, as will be shown in the following section.
The single meter reading is stored in two separate memories: should either of the two memories become
corrupted, it is automatically replaced by the other.
Only if both memories should become corrupted simultaneously would the data be lost; the probability of this hap-
pening is practically nil, because the two memories are never used at the same moment and the levels of protec-
tion against electrical and radio disturbances are at the maximum level required by the standards (see section 11).
17.
8
Adjustment of meter readings
The adjustment of all meter readings serves to equalize the readings of external meters to those of the IET 71..
meters. Examples :
– the meter is installed after the volumetric meter installed has totalled the readings. Normally, when the turbine
volumetric meter is first installed the plant is started up and the meter starts to measure the volume flowing past
it (m
3
).
IET 71.., when first installed and set in operation, has all its meters set to zero or at the minimum amount necessary
for testing. The metering of m3 by the volumetric meter is, therefore, different from the metering of the same m
3
by
the electronic meter: it is possible to reconcile the two meter readings.
– the meter is installed as a replacement for a pre-existing meter; in this situation also it is useful for the client to
have the readings on the new meter which start from those already made by the old one.
The adjustment operation must obviously be protected by a seal, since any alteration would mean different data
readings.
The basic data, however, is always stored in the meter and must not be altered in any way, since they are fiscal
data ; the next section describes these meter readings in more detail.
In the memories are stored the basic meter readings together with the adjusted values; in this way the true readings
are securely safeguarded, as are the adjustment values; the figures to present to the user are the basic meter readin-
gs, corrected by the adjustment values.
Furthermore, all data which has undergone any adjustments is recorded, in order to identify errors and intentional
tamperings.
17.
9
Data storage (DATA LOGGER) of meter readings, power and flow peaks, and errors
The unit incorporates a DATA LOGGER which can store 52 weeks of meter readings and operational data: by this
means it is possible to understand, check and if necessary interpolate all the data for a whole year.
– RECORDING METER READINGS: every week (at around midnight on Sundays) a recorded the four fundamental
meter readings made up to that moment (see section 17.
8
) with day and date.
– RECORDING OF POWER & FLOW PEAKS: every week are recorded the values of maximum power and flow
reached that week.
The maximum flow of the vector fluid is calculated as the mean over a certain number of minutes (chosen via
Telemanagement), so as to avoid sudden insignificant peaks; the same criteria are followed for power.
The power peaks are recorded indifferently for heating and for cooling, since it is very easy to understand, on the
basis of the season, if reference is to one or the other.
– RECORDING OF ERRORS (ALARMS): each type of alarm (see section 16) is recorded both when it is triggered
and when it ceases, with exact date and time. The system records up to 10 of these events; after this it cancels
the oldest to leave space for new onesi.
Everything having reference to the DATA LOGGER can be set and read via Telemanagement C-Bus.
