Proface LT4300M - 5.7 Modular HMI + Control" - Manual (Page 32)

LT System General Implementation Rules
32
Wiring Rules and Recommendations
Introduction
There are several rules that must be followed when wiring the LT system.
Wiring Guidelines
The following rules must be applied when wiring a LT system:
 I/O and communication wiring must be kept separate from the power wiring. Route these 2 types
of wiring in separate cable ducting.
 Verify that the operating conditions and environment are within specification.
 Use proper wire sizes to meet voltage and current requirements.
 Use copper conductors.
 Use twisted-pair, shielded cables for analog, and/or fast I/O.
 Use twisted-pair, shielded cables for networks, and fieldbus.
 For the power connector, refer to DC power supply wiring diagram (see page 77).
 When terminals A2 and B2 (signal name: Q1, Q0) are wired to external I/O, use the same power
source for external I/O and the LT. Refer to Power Supply Connections.
 If you use a temperature sensor with thermocouple inputs, make sure you use the
compensation cable.
 Prevent temperature changes to the thermocouple connection terminal. Correct temperature
measurement may not be possible if the thermocouple cold junction (LT’s thermocouple
compensation wiring to the connection terminal) experiences temperature changes.
1 Multipoint grounding is permissible if connections are made to an equipotential ground plane
dimensioned to help avoid shielded cable damage in the event of power system short circuit
currents.
For more details, refer to Grounding Shielded Cables (see page 38).
DANGER
HAZARD OF ELECTRIC SHOCK, EXPLOSION OR ARC FLASH
 Disconnect all power from all equipment including connected devices prior to removing any
covers or doors, or installing or removing any accessories, hardware, cables, or wires except
under the specific conditions specified in the appropriate hardware guide for this equipment.
 Always use a properly rated voltage sensing device to confirm the power is off where and when
indicated.
 Replace and secure all covers, accessories, hardware, cables, and wires and confirm that a
proper ground connection exists before applying power to the unit.
 Use only the specified voltage when operating this equipment and any associated products.
Failure to follow these instructions will result in death or serious injury.
WARNING
IMPROPER GROUNDING CAN CAUSE UNINTENDED EQUIPMENT OPERATION
 Use cables with insulated shielded jackets for analog I/O, fast I/O and communication signals.
 Ground shielded cables for analog I/O, fast I/O and communication signals at a single point 1 .
 Always comply with local wiring requirements regarding grounding of cable shields.
Failure to follow these instructions can result in death, serious injury, or equipment
damage.