Technical Description; Area Of Application; Structure - Siemens SIWAREX JB Instruction Manual

1 Technical Description

1.1 Area of Application

The SIWAREX JB junction box made of die-cast aluminum serves for connecting
load cells with the weigh module. Up to four load cells can be connected in parallel
in one junction box (fig. 1-1). Another junction box must be connected in parallel by
a cross connection in case of more than 4 load cells (fig. 1-2).
Load cells with wire strain gages in 4 and
6-wire technology can be connected in
parallel.
The cable connection from the junction box
to the weigh module and between two
junction boxes must be made in 6-wire
technique.
The SIWAREX JB junction box may only
be used with low voltages of ≤ 30 V.
LC LC
LC LC LC LC
LC LC
LC LC
Fig. 1-1 Connection principle of

1.2 Structure

The housing is made of a heavy duty, powder-coated die-cast aluminum AlSi12.
It consists of bottom part and lid. It is dustproof and splash proof according to the
IP 66 degree of protection. The cables are fed into the housing through screw
cable glands. High electromagnetic compatibility (EMC) is only achieved by the
large area of the shield in the screw cable gland. The screw cable glands are made
of nickel-plated brass.
The electrical conductors are wired by spring terminals. The spring terminal
technology guarantees vibration-free, maintenance-free connections. The contact
reliability is permanently guaranteed.
A potential equalization line can be connected via a PAL terminal.
SIWAREX JB junction box in aluminum housing – Instruction Manual
A5E00400544B
4/6 4/6
6 6
JB JB W W
LC = Load Cell
JB = Junction Box
W = Weigh module
4 load cells
LC LC
4/6 4/6
LC LC LC LC
JB JB
LC LC
LC LC
LC LC
LC LC LC LC
JB JB
LC LC
LC = Load Cell
JB = Junction Box
LC LC
W = Weigh module
Fig. 1-2 Connection principle of
8 load cells
6 6
W W
6 6
5