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The accuracy is checked by comparing the flow
rates. The pressure and temperature values of
the unit under test corrected with reference to
the master meter have already been taken into
account here:
F
= 100% x (((Q
P
P
T
)) - 1)
P
The following applies:
p
= relevant absolute pressure on the unit under test
P
The following also applies:
for BK-G...E: T
= (273.15 + {t
P
where t
= relevant gas temperature on the unit
g
under test in °C (display)
for BK-G...ET and BK-G...ETe:
T
= (273.15 + {t
}) K (t
P
b
cal data))
▷ The curly brackets mean "numerical value of".
▷ On a nozzle test rig with a known flow rate,
step 4 can be omitted.
▷ The error calculation is based on PTB Testing
Instructions, Volume 29: "Messgeräte für Gas –
Gaszähler" (Measuring instruments for gas – gas
meters), Edition 2003.
Recommission the previously switched off com-
munication modules.
Pulse test with a given volume
Master meter test procedure
V
N
19
18
Start the pulse test on the unit under test –
marker 18.
4 Start the test on the master meter – marker 19.
5 Record the pulses from the unit under test.
▷ The unit under test generates the volume pulses
on the optical interface each time the lowest-
order decimal place on the index display is in-
cremented.
6 The test volume is achieved and the test ends –
marker 20.
7 End the pulse test on the unit under test using
any command – marker 21.
▷ Measurement is terminated automatically after
90 minutes.
x p
x T
) / (Q
x p
P
N
act,N
}) K
g
see page 15 (Techni-
b
20
8 Determine the volume on the unit under test V
V
= N x V
P
N
= number of pulses
V
= pulse value in m³
Imp
9 Read off the volume on the unit under test.
x
The inherent error of the master meter is to be
N
taken into account if applicable:
V
= V
act,N
N
0 Determine the measuring deviation on the unit
under test:
F
= 100% x (((V
P
▷ The pressure and temperature values of the unit
under test corrected with reference to the master
meter have already been taken into account here.
The following applies:
p
= relevant absolute pressure on the unit under
P
test
The following also applies:
for BK-G...E: T
where t
= relevant gas temperature on the unit
g
under test in °C (display)
for BK-G...ET and BK-G...ETe:
T
= (273.15 + {t
P
cal data))
▷ The curly brackets mean "numerical value of".
▷ The error calculation is based on PTB Testing
Instructions, Volume 29: "Messgeräte für Gas –
Gaszähler" (Measuring instruments for gas – gas
meters), Edition 2003.
Recommission the previously switched off com-
munication modules.)
RTC test
▷ The climatic conditions must be maintained con-
stant at 22 ± 5°C during the entire test duration.
Temperature changes in 24 hours ≤ 2 K.
▷ Ensure that conditions remain sufficiently stable
during the measurement.
▷ The accuracy of the time count can be verified
with this test.
21
Acclimatize the unit under test and place next
to the time reference unit.
If necessary, activate the time display on both
units.
Ensure synchronous reading by taking a photo.
4 Observe a min. testing time of 24 hours.
5 Repeat steps and .
6 The clock deviation of the unit under test must
not exceed the maximum admissible deviation.
Maximum admissible deviation = 100 ppm in
24 hours.
GB-13
Imp
/ (1 + F
/100)
N
x p
x T
) / (V
x p
P
P
N
act,N
= (273.15 + {t
}) K
P
g
}) K (t
see page 15 (Techni-
b
b
:
P
x T
)) - 1)
N
P
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