Pinnacle Systems STTS - Manual (Page 33)

27
ANNEX C (Installation Practices for Industry)
The proper installation of the STTS Mat System is essential if the system is to operate properly. This
section provides the user with general wiring, grounding, and shielding guidelines that should be followed
in industrial installations.
These guidelines are presented as a tool in avoiding potential electromagnetic interference (EMI, also
called Noise) problems. Because of the many ways that EMI problems can be generated, these
guidelines are not meant as a cure-all, but instead as a list of basic rules that will help suppress or
eliminate most common sources of EMI interference. These Guidelines are not a substitute for the safety
practices called out in Local Electrical Codes or the National Electrical Code which is published by the
National Fire Protection Association. If any discrepancies exist, the Local or National Codes must be
followed. IT IS THE RESPONSIBILITY OF THE USER to determine what installation practices must be
followed to conform to all National and Local Codes.
These Guidelines are organized into the following sections:
1) Raceway Layout (Wiring) Considerations
2) Grounding
3) Shielding of Cables
1.0) RACEWAY LAYOUT CONSIDERATIONS
1.1) RACEWAY PLANNING:
Before planning a raceway layout, all wires and cables in or around the controller and mat
wiring should be broken into the following categories:
TYPE 1: High-Power Conductors
This category includes all high-power conductors. High power lines are usually quite tolerant
of EMI noise problems but may also generate large amounts of EMI noise that may disturb
other conductors near them. These conductors include:
1) High-Power AC and DC Lines
This includes all power lines to and from mechanical switches, relays, solenoids,
motors, generators, arc welders, etc.
TYPE 2: Low-Power Conductors
This category includes all low-power conductors. Low-power lines are usually less tolerant of
EMI noise problems than Type 1 conductors but also generate less EMI noise. These
conductors include:
1) STTS Mat Wiring Cables. This is the cabling that connects the safety mat to the
controller.
2) Serial Communication Cables. These connect between processors and remote
units such as displays, terminals, or other processors.
3) Low-Power AC/DC Switcher Lines. These lines include all lines that carry low
currents and input circuits with short time-constant filters that are designed to
detect short, single event pulses. Typically, these lines are connected to devices
such as proximity switches, photo-electric sensors, and low power analog or
digital devices.
TYPE 3: System Interconnect Cables
These cables interconnect the system components within an enclosure. They include:
1) ALL Ribbon Cables. This includes cables that interconnect system units or
connect units to relay boards.