Siemens SIWAREX JB User manual

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SIWAREX JB
Aluminum Housing
Instruction Manual Edition 03/2006

SIWAREX JB junction box in aluminum housing – Instruction Manual
A5E00400544B 2
Table of Contents
Table of Contents............................................................................................. 2
Warning and Safety Terms.............................................................................. 3
General.............................................................................................................. 4
1Technical Description.............................................................................. 5
1.1 Area of Application..................................................................................... 5
1.2 Structure .................................................................................................... 5
1.3 System Configuration................................................................................. 6
2Installation/Assembly.............................................................................. 7
2.1 Installation.................................................................................................. 7
2.2 Connection................................................................................................. 7
2.3 Installation................................................................................................ 11
2.4 Spring Terminal Connection Technique................................................... 13
3Commissioning...................................................................................... 14
4Technical Data........................................................................................ 15
4.1 Functional Data........................................................................................ 15
4.2 Device Version......................................................................................... 15
4.3 Explosion Protection ................................................................................ 15
4.4 Electromagnetic Compatibility.................................................................. 16
4.5 Dimensions .............................................................................................. 16
5. Care and Maintenance........................................................................... 17
6. Ordering Data......................................................................................... 18

SIWAREX JB junction box in aluminum housing – Instruction Manual
A5E00400544B 3
Warning and Safety Terms
DANGER
Means, that death, severe injury to persons or damage to equipment will be
caused if the respective safety measures have not been taken.
WARNING
Means, that death or severe injury can be caused if the respective safety
measures are not taken.
CAUTION
With a warning triangle means that failure to take the necessary precautions may
lead to minor injury.
CAUTION
Without a warning triangle means that failure to take the necessary precautions
may lead to property damage.
IMPORTANT
Means that failure to observe the appropriate instructions may lead to an
undesirable result or condition.
NOTE
Means a note of a possible benefit if recommendations are followed.
Qualified personnel as referred to in the safety instructions in this manual and on
the product itself are individuals who are familiar with the installation, assembly,
initial start-up and operation of this product. They must be authorized and qualified
to install, start and maintain devices, systems and circuits in accordance with
national safety rules and regulations.
Copyright © Siemens AG 2006 All rights reserved
Circulation or duplication of this document, utilization and
disclosure of its contents are not permitted unless explicitly
approved. Offenders will be liable for damages. All rights reserved,
including rights created by granting of patents or registration of a
utility model or design.
Siemens AG
Automation and Drives
Process Instrumentation and Analytics
D-76181 Karlsruhe
Disclaimer
We have tested the contents of this document for compatibility with
the hardware and software described. This does not exclude the
possibility of discrepancies, in which case we do not guarantee the
complete compatibility of this document. The information in this
document is assessed regularly and any necessary corrections are
included in the next revision. We are grateful for any suggestions
for improvement.
© Siemens AG 2006
Subject to technical changes

SIWAREX JB junction box in aluminum housing – Instruction Manual
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General
Intended Utilization
Intended utilization means that this product is only to be utilized within the
limitations defined in the technical specifications and purposes of use in this
operating manual.
There are no dangers associated with this device when conforming with the safety
notes and the intended utilization.
The fail-safe and secure operation of this device depends on proper transportation,
storage, installation and assembly as well as on careful operation and
commissioning.
Proper operation of this device can only be ensured if the specifications provided in
the technical data are observed.
Improper handling can cause death, bodily harm and damage to equipment.
Notes on Product Liability
We expressly point out that the nature of the product is described exclusively and
conclusively in the sales contract. The content of this product documentation is not
part of an earlier or existing agreement, promise or legal relationship and neither
shall it change any of these. All Siemens obligations ensue from the respective
contract of sale which also contains the full and exclusively valid liability regulation.
The provisions about product liability specified in the contract of purchase are not
extended or limited by the information provided in this document.
Delivery Notes
The respective scope of delivery is listed on the enclosed shipping documents
according to the valid contract of sale.
Please observe the instructions printed on the packaging when opening. Check
that the delivered goods are complete and undamaged. In particular, compare the
order number on the type plate with the order data.
Please read this manual before starting work! It contains important instructions
and data which guarantee the general safety and functionality of this device when
observed. This considerably simplifies handling of this product and leads to reliable
measuring results.

SIWAREX JB junction box in aluminum housing – Instruction Manual
A5E00400544B 5
LC
LCLC
LC
LC
JB W
6
4/6
LC
LCLC
LC
LC
JB W
6
4/6
LC
LCLC
LC
LC
JB
LC
LCLC
LC
LC
JB
6
6
4/6
W
LC
LCLC
LC
LC
JB
LC
LCLC
LC
LC
JB
6
6
4/6
W
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.
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.
Fig. 1-1 Connection principle of
4 load cells
LC = Load Cell
JB = Junction Box
W = Weigh module
LC = Load Cell
JB = Junction Box
W = Weigh module
Fig. 1-2 Connection principle of
8 load cells

Revision 03.06 Technical Description
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1.3 System Configuration
The SIWAREX JB junction box is used in technical weighing systems for parallel
connection of up to four wire strain gage load cells. If more than four load cells
are to be connected to a weigh module, several junction boxes can be connected
to each other by cross connections. Load cells can be connected in 4 and 6-wire
technology.
The technical data of the weigh module and load cells used must be observed
with the maximum number of load cells. The total resistance of the parallel
switched load cells must be in the range of the permissible load resistance of
the weigh module.
The junction box is connected with the weigh module with a signal cable.
A shielded cable with six wires must be used as the signal connection.
We recommend the SIWAREX cable Li2Y2x0,75St+2x(2x0,34St)-CY:
•7MH4 702-8AG, orange coated, for standard applications or
•7MH4 702-8AF, blue coating, for Ex-applications.
The maximum cable length between load cells and weigh module can be found
in the technical data of the weigh module. Intermediate elements such as
Ex disconnectors must be taken into account.

SIWAREX JB junction box in aluminum housing – Instruction Manual
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2 Installation/Assembly
2.1 Installation
The SIWAREX JB junction box may only be installed and connected by qualified
personnel.
2.2 Connection
The connection of load cells with 4 or 6-wire technique to a weigh module must be
made according to the wiring diagrams in fig. 2-1 or fig. 2-2, page 8. Analogously,
several load cells are also connected in parallel.
The pinout of the terminals is shown in fig. 2-3, page 9. Four terminals are
connected in signal blocks with a plug-in bridge.
The cable shields in the EMC screw cable glands should cover a large area
(fig. 2-4, page 9). EMC cable glands and sealing plugs are delivered with the
junction box. They should be mounted according to the number of load cells.
Unused openings in the housing should be sealed with sealing plugs.
The pinout of the screw cable glands is shown in fig. 2-5, page 10.
When connecting load cells using 4 wires, two bridges are absolutely necessary:
Bridge 1: EXC- to SENSE-
Bridge 2: EXC+ to SENSE+
IMPORTANT
If the two bridges EXC-/SENSE- and EXC+/SENSE+ are missing in load cells in
4-wire technology, this can be signaled by the weigh module as a wire break.

Revision 03.06 Installation/Assembly
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Fig. 2-1 Load cell connection by 4-wire technique
Fig. 2-2 Load cell connection by 6-wire technique

Revision 03.06 Installation/Assembly
SIWAREX JB junction box in aluminum housing – Instruction Manual
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Fig. 2-4 Shield in the screw cable gland
Fig. 2-3 Terminal block

Revision 03.06 Installation/Assembly
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Fig. 2-5 Pinout of the screw cable glands
LC = Load cell Input
W = Output to weigh module, to the Ex barrier or other junction box
EPB = Equipotential bonding connection
LC LC LC LC
W W
EPD