10
Rev G
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TR400 Wiring & DIP Switches
Recommended wiring practices
Recommended wiring practices must be followed when wiring industrial equipment such as the
TR400. Failure to follow the practical wiring practices listed below could result in an injury to
persons or damage to equipment.
Wiring
practices
The following is a list of recommended wiring practices for installing industrial
equipment. It is critically important that you observe and follow these wiring
practices when wiring the TR400.
• All control signals must be shielded cable. The shield must be tied to common or
earth ground at the receiving end only. In some environments, earth ground may
contain excessive electrical noise. If you encounter problems using earth ground
as a shield-tie point, switch the shields to signal common. All connections to the
controller are considered signal unless they carry AC voltage.
• Never use a shielded cable with unused conductors. The unused conductors act
as antennas. Attempting to tie the unused conductors to ground or other signal-
carrying wires will create different antenna configurations. In many cases, an
unshielded wire could be less susceptible to electrical noise. Always make sure
that a shielded cable with the correct number of conductors is pulled.
• All control signals must be separated from power wires. Power wiring includes
any AC or DC wires carrying voltages with a current potential of greater that one
(1) amp or a voltage greater than 24 volts. This includes, but is not limited to,
115 Vac, 230 Vac, and 460 Vac. Do not bundle shielded cables and power wires
together.
• Do not run signal cables along high magnetic or electrostatic generators. This
includes, but is not limited to motors, fans, contactors, igniters, etc. Aluminum
shielded cable does not stop magnetically induced noise; braided shielded cable
only partially reduces magnetically induced noise.
• An earth ground wire must be installed on microprocessor-based equipment
when required. Do not rely on the enclosure’s contact with the panel for earth
ground. Earth ground is often used in noise-rejection circuitry as well as for
safety.
• Contactors, solenoids, and relay coils connected to the same AC power source or
in the same enclosure panel as the controller must be suppressed with a
capacitor-resistor filter across the coil. These can be made with a 1 kV capacitor
and a ¼-watt resistor in series, or they can be purchased in a pre-made package.
Use a capacitance value of 0.1 µF or larger and a resistance value of 500 ohms or
less.
• When AC voltage is stepped down for use with equipment, a capacitor-resistor
network or a filter should be placed across the secondary.
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