Avery Berkel CX20 SERIES, Service Manual

Page: 183 / 353

17 — Transducer
17–3 CX20/CX30/CX34 Service Manual
17.1 Description
17.1.1 Transducer Assembly CX20/CX30
Refer to Figure 17.1.
On the CX20/CX30 machines the transducer is fitted centrally, in the the base of
the machine to the chassis. The CX20 W does not have an internal transducer,
it is connected to a remote weighing patform, the CX9/A702. For further details
of the CX9/A702 see Section 18.
The transducer assembly comprises a base, a transducer housing, a mounting
block and an overload stop.
The base is made of cast metal and enables the transducer to be attached to a
unit at four fixing positions. The mounting block is also made of cast metal and
has four threaded holes. Two of these holes are to attach the mounting block to
the transducer housing, the other two holes are to attach a cross assembly on
which load will be placed.
The transducer housing is machined to precision tolerances and is attached to
the base at one end by two socket–head screws. The mounting block is
attached at the other end of the transducer housing by two socket–head screws.
Any weight on the mounting block is transmitted through the transducer housing
to the base, causing the transducer housing to distort physically.
The core of the transducer housing is hollow, and several grooves are machined
on the outer surface. The grooves and hollow housing are provided so that
applied weight causes the transducer housing to distort by a large amount in a
predictable manner.
Four self–adhesive, strain pads are attached to the transducer housing around
its inner wall. Each pad is connected by wire to a circuit PCB, which partly
covers the hollow housing at one side. The other side of the hollow housing is
partly covered by a protective aluminium plate.
Figure 17.1 Transducer Assembly (CX20/CX30)