Sartorius WZA25-NC Application Instructions
Application Instructions | Applikationshinweise
Sartorius WZA25-NC
98648-018-08
English – page 2
Deutsch – Seite 9
2
Contents 1. General
1. General . . . . . . . . . . . . . . . . . . 3
1.1 Intended Use . . . . . . . . . . . . . . 3
1.2. Connections. . . . . . . . . . . . . . . 3
1.3. Securing the Weigh Cell ......3
2. Transducer................4
3. IP Protection ..............5
4. Internal Calibration......... 6
5. Cooling Air Operation ....... 6
6. Enclosure.................7
7. Interconnection
of Multiple Cells ...........8
7.1 Interconnection
of Pneumatic Functions ...... 8
7.2 Interconnection
of Electronic Functions.......8
8. Optimal Operating Point..... 8
These application instructions are
a supplement to the accompanying
installation instructions. The application
instructions address particular features
of the WZA25-NC.
Please read the accompanying installa-
tion instructions carefully.
1.1 Intended Use
The WZA25-NC weigh cell was devel-
oped for automatic weighing facilities
and metering units in the pharmaceutical industry in particular.
Multiple cells can be interconnected
in a row, 25 mm apart from each other.
It is also possible to interconnect them
in two rows, where a 25-mm distance
can be achieved.
Using special measures, a protection
rating of IP68 can be achieved when
the system using the weigh cell is being
cleaned. This function also has a pneumatic drive, which easily enables the
interconnection of multiple cells (see
Section „Interconnection of Multiple
Cells“).
The cells have a built-in calibration
weight, which can be used to check
that the cells are functioning properly
or to readjust the sensitivity of the cells.
1.2 Connections
8 5 9
10
6
d 6 H8; 6 deep
Mounting surface
1
M6; 6 deep
2
6 and 7 are sintered filters.
Pos. Description
Mounting surface
Threaded hole for mounting
Positioning holes
Electrical connection
Pressure inlet weight circuit
6 bar, d 3 mm
All dimensions are given in millimeters
3
6 H8; 6 deep
Pos. Description
Pressure inlet closing mechanism
6 bar, d 3 mm
Air inlet for rinsing cycle < 50 mbar
Air outlet for rinsing cycle
< 50 mbar
Pressure outlet for and
1.3 Securing the Weigh Cell
Secure the weigh cell at low tension to
the mounting surface 1 (second Figure)
with an M6 screw. Observe the maximum screw installation depth.
10
Use the positioning holes 3 and 4 to
align the weigh cell exactly.
7
Use the M6 fixing screw to connect to
4
the device ground in order to divert
electrostatic charges.
3
d
d
2. Transducer
The weigh cell is equipped with a partially beveled cylindrical stud (see Figure) for securing a
transducer at the customer‘s premises. The beveling (2.5 mm) serves to secure the transducer
in a specified direction of rotation.
The transducer can be installed on this stud using clamps, for example. The transducer
should consist of conductive, non-magnetic material in order to minimize electrostatic and
magnetic interference. The transducer must weigh 5 g ± 0.1 g, so that the full weighing
capacity of 20 g can be achieved. It must be smaller than 10 g in order to use the internal
calibration function. Remove the transducer when transporting the weigh cell.
The stud is overload protected. Do not exceed the maximum forces and torque. The stud
may bend due to the effects of forces or torque.
Bending can occur if torque is greater than 2 mNm for a 5 g transducer.
Model Max. torque Screwing torque Max. force opposite to Max. forces
M
WZA25-NC 0.1 Nm 0.5 Nm 2 N 2 N
, My, Mz direction of load (-Fz) Fx, Fy, F
x
z
4
8
9
Shield plate
Gap
Seal ring
3. IP Protection
The cell has a rating of IP44 in normal weighing mode. This protection rating is only valid
when there is a gap between the shield plate and the seal ring.
The gap is sealed by applying the pressure inlet (7) at 6 bar. A closing mechanism is set
in the space, which pulls the stud and shield plate against the seal ring. Observe a distance
of approx. 1 mm between the transducer and the rest of the equipment. In this position,
the cell does not provide a weight value; instead it displays the error message, “H.”
After the closing mechanism is opened, the weigh cell requires some time to restabilize.
The connection side of the weigh cell can be sealed by placing a seal between the lower
edge of the weigh cell housing and the mounting plate. Use as soft a sealing material as
possible (e.g., Sili-Rex silicone foam round cords from Rexio GmbH Co. KG, Westerrönfeld,
Germany) in order to minimize the force on the cell housing. This process causes the plug
and pressure outlet to be outside of the contamination and cleaning area (process side).
The connection side has a rating of IP44.
Cleaning
Apply overpressure to ensure that cleaning fluid does not penetrate the weigh cell.
To do so, apply an overpressure of max. 50 mbar through overpressure inlets 8 and 9 to the
weigh cell interior (use dry filtered oil-free and particle-free air only).
Once cleaning is successfully complete, the closing mechanism can be opened, and air can
continue to be blown into the cell. The air exits through the gap and dries the area after
cleaning.
Process side
Connection side
5
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