commissioning
the measuring point
Before using the Deltabar S for measuring differential pressure, clean the pressure piping
and fill the device with medium. The measuring span (upper range-value – lower
range-value) is either preset (see pages 49 and 50), or only the lower range-value is set
during commissioning, as described below.
#
Valves
Significance
1
Close 3
2
Fill measuring system with medium
Open A, B, 2, 4
Lets medium in
3
If appropriate clean pressure piping*
– for gases with compressed air
– for liquids by washing out
Close 2 and 4
Shut off transmitter
Open 1 and 5*
Blow out/wash out
pressure piping
Close 1 and 5*
Close valves after
cleaning
4
Let air out of transmitter
Open 2 and 4
Let in medium
Close 4
Close negative side
Open 3
Connect positive and
negative side
Briefly open 6 and 7
then close again
Fill transmitter with
medium and let out air
5
Set zero and display to zero
Note:
The following entries are only
appropriate here if:
– the process cannot be shut off
and
– the tapping points (A and B) are geodatical-
ly at the same height.
If the flow can be shut off then this calibration
of zero and display is to be carried out
after
step 6.
V0H3:
➤
Set 4 mA
automatically
Acting pressure is
taken as lower
range-value
V0H6:
➤
Sets bias pressure
automatically
Set display to "0"
(position calibration)
6
Make measuring point ready for operation
Close 3
Shut off positive from
negative side
Open 4
Close negative side
Now:
1*, 3, 5*, 6 and 7 are closed
2 and 4 are open
A and B are open (if present)
Set lower range-value and display to zero
If the flow can be shut off then this calibration
of lower range-value and display is to be carried
out here. Step 5 is therefore ignored.
7
Shut off flow
V0H3:
➤
Sets 4mA
automatically
Active pressure is
taken as zero
V0H6:
➤
Sets bias pressure
automatically
Set display to "0"
(position calibration)
Open flow
*
For arrangements with five valves only
#
Valves
Significance
8
Select curve
see next page
9
Measuring point is ready for operation
Caution!
When opening and closing valves to the
process, care must be taken to avoid
overheating
or
one-sided
overloading
(beyond specifications) of the measuring
cell. If the measuring range is adjusted, the
output signal may not lead to impermissible
jumps in the control loop.
+
2
A
B
6
7
4
3
BA174Y28
inlet valve
inlet valve
equalising valve
shut-off valve
shut-off valve
vent valves on
transmitter
PMD 25 K
Preferred installation for gases
process
3-way
manifold
+
2
1
5
A
B
6
7
4
3
+
–
shut-off
valve
shut-off
valve
inlet
valve
inlet
valve
drain
cock
drain
cock
equalising
valve
BA174Y70
vent valves on
transmitter
PMD 25 K
Preferred installation for fluids
trap
trap
3-way manifold
Caution!
Deltabar S
7 Flow Measurement
Hauser
51
