Karel MS128, Installation & Maintenance Manual

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Karel MS128 Installation & Maintenance Guide
Edition 3.2
44
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R
EMARK
The internal modules must be installed from left to right, starting from SPS128
Power Supply Module.
IMPORTANT
The equipment can be installed only by the service personnel.
The area behind the front cover is not for operator access, hence the
front cover can be opened only by the service personnel.
The mains socket should be installed near the equipment or should be
easily accessible.
II.1. GROUNDING
The chassis ground of the MS128 system also serves as the signal ground, which
takes place on all the cards as a reference for the existing signals.
The chassis ground has an utmost importance for the protection of the system
against lightning or high voltage coming through lines, extensions or mains.
The chassis ground is partly established through the mains cable of the system,
which is equipped with the ground wire. Due to this reason, it is recommended to
operate the system over a mains plug that is properly grounded.
Checking whether the mains ground is proper or not requires some special devices.
But it is possible to have a rough idea about the mains ground simply by measuring
the voltage across:
•
The phase and the neutral; it must be in-between 180 VAC and 260 VAC.
•
The ground and the neutral; it must be around 1-2 VAC.
However, even if the mains outlet is properly grounded, it may not be sufficient by
itself for MS128. So, it is also strongly recommended to make a separate and
private ground connection for MS128. The best way to construct an ideal ground for
this purpose is to insert a metal bar (of at least 1.5 m length and 1.5 cm radius,
copper is preferable) into the earth, as illustrated in Figure B-2.
To establish the connection of the system to such a ground surface, the ground
screw (labeled with , as illustrated in Figure A-5) must be connected to the
ground surface.