GB-12
D
GB
F
NL
I
SK
▷
The following also applies:
for BK-G…E: T
P
= (273.15 + {t
g
}) K
where t
g
= relevant gas temperature on the unit
under test in °C (display)
for BK-G...ET:
T
P
= (273.15 + {t
b
}) K
where t
b
= 15°C (see page 15 (Technical data)):
T
P
= 288.15 K
for BK-G…ETe:
If the converted volume V
b
is taken for V
P
:
T
P
= (273.15 + {t
b
}) K (t
b
If the non-converted volume V
P
is taken for V
P
:
T
P
= (273.15 + {t
g
}) K
where t
g
= relevant gas temperature on the unit
under test in °C (display)
▷
The curly brackets mean “numerical value of”.
6
Stop execution of the cyclic test – marker 11.
Briefly press the selection key twice in order
to stop the measurement.
▷
A beep confirms interruption of the measurement.
▷
Measurement is terminated automatically after
5 hours.
▷
The error calculation is based on PTB Testing
Instructions, Volume 29: “Messgeräte für Gas –
Gaszähler” (Measuring instruments for gas – gas
meters), Edition 2003.
Pulse test
The pulse test is designed for checking the meter with
a master meter. The recorded volume is provided by
pulses which are emitted via the optical interface.
Test load and minimum test volumes for the test with
index readout:
Type
Q
max
in
m
3
/h
Cyclic
volume
in dm
3
Test volume in dm
3
at
Q
min
0.2 Q
max
Q
max
BK-G1.6
2.5
1.2
36
72
72
BK-G2.5
4.0
1.2
36
72
72
BK-G4
6.0
1.2
36
72
72
BK-G2.5
4.0
2
60
120
120
BK-G4
6.0
2
60
120
120
BK-G6
10
2
60
120
120
BK-G6
10
4
120
240
240
BK-G6
10
6
180
360
360
BK-G10
16
6
180
360
360
BK-G16
25
6
180
360
360
BK-G25
40
12
360
720
720
▷
Pulse value V
Imp
, see page 15 (Technical data).
▷
This test can only be carried out when the opti-
cal communications link has been established.
The procedure depends on your user software.
Establish the optical communications link, see
page 7 (Establishing an optical communica-
tions link).
Interrupt communication to the installed commu-
nication modules before starting the test so that
the measurement accuracy will not be adversely
affected.
As of step 3, continue as described in one of the two
following sections.
Pulse test at a constant flow rate (optical
interface)
Master meter test procedure
∆t
N
∆t
P
13 14
15
16
17
12
Q
N
Set the test flow rate.
4
Start measuring the reference time ∆t
N
at mark-
er 12.
▷
Marker 12 indicates the release of the test flow
rate on the master meter.
5
Immediately afterwards, start the pulse test on
the unit under test – marker 13.
▷
Then the unit under test generates the volume
pulses on the optical interface each time the
lowest-order decimal place on the meter display
is incremented – marker 14. The test begins.
6
As soon as the required minimum test volume
has been reached on the unit under test, the
time measurement on the unit under test can
be stopped – marker 15.
7
End the pulse test using any command – mark-
er 16.
▷
Measurement is terminated automatically after
90 minutes.
8
Shut off the gas flow to the master meter –
marker 17.
9
Determine the volume on the unit under test V
P
:
V
P
= N x V
Imp
N
= number of pulses during Δt
P
V
Imp
= pulse value V
Imp
0
Calculate the flow rate on the unit under test:
Q
P
= V
P
/Δt
P
Read off the flow rate on the master meter or
calculate if necessary:
a) taking into account the inherent error of the
master meter:
Q
act,N
= V
N
x 3600 s/h / ((1+F
N
/100) x Δt
N
)
b) If the inherent error of the master meter has
already been taken into account in the dis-
played volume (V
N
= V
act,N
):
Q
act,N
= V
act,N
x 3600 s/h / Δt
N
