PTZ-BOX 5.0 User manual, document edition: 13
9
Vm
n
= Vm
p
+ dVm
Vb
n
= Vb
p
+ dVb
E
n
= E
p
+ dE
M
n
= M
p
+ dM
During normal state, emergency counters are stopped.
If the unit operates in emergency state, all calculated increments are added up to emergency
counters:
Vme
n
= Vme
p
+ dVm
Vbe
n
= Vbe
p
+ dVb
Ee
n
= Ee
p
+ dE
Me
n
= Me
p
+ dM
During emergency state, the main counters Vb, E and M are stopped. Vm counter is always
active.
Emergency state of PTZ-BOX 5.0 is active as long as an alarm from a system group is active.
1.2.4
Calculation of conversion factor C
The main objective of the gas volume conversion device is to calculate conversion factor to base
conditions
C
, which is later used to convert values obtained at the measurement conditions into
values at the base conditions.
To calculate coefficient
C
, following values are used:
-
pressure
p1
and temperature
t
, coming from modules at the left side of Figure 1.
-
compressibility factors: at measurement conditions
Z
and at base conditions
Zb
–
computed
basing on measured values of gas pressure, temperature and current gas composition.
If values of pressure or temperature will exceed the ranges determined for currently used algorithm,
an alarm of algorithm error will be generated, and further results will be saved into emergency
counters. Calculation of compressibility factors is possible even if values of
p1
and
t
will be out of
ranges (however, keep in mind, that uncertainty of performed calculations in this conditions will be
increased). If chosen calculation algorithm is unable to perform further computation, then last
calculated values of
Z
and
Zb
are used.
-
base pressure
pb
and base temperature
Tb
.
Both of those values are describing the base conditions, on which values obtained at measurement
conditions are going to be converted. Additionally, combustion temperature for computation of the
superior calorific value Hs (
T1
).
Basing on parameters presented before, a Conversion factor to base conditions
C
is calculated:
𝐶 =
𝑇𝑏 [𝐾]
𝑝𝑏 [𝑘𝑃𝑎]
×
𝑝1 [𝑘𝑃𝑎]
𝑡 [𝐾]
×
1
𝐾1
(1a)
