Rockwell-automation 1769-IF16V Compact High Density Analog Input Modul Instrukcja Użytkownika Pobierz pdf (Strona 21)

Publication 1769-UM018A-EN-P - October 2008 21

Installation and Wiring Chapter 2

System Wiring Guidelines

Consider the following when wiring your system:

• All module commons (COM) are connected in the analog

module.

• The analog common (COM) is not connected to earth ground

inside the module.

• Channels are not isolated from each other.

• To ensure optimum accuracy, limit overall cable impedance by

keeping your cable as short as possible. Locate the I/O system

as close to your sensors or actuators as your application will

permit.

• Use Belden 8761, or equivalent, shielded wire.

• Under normal conditions, the drain wire and shield junction

must be connected to earth ground via a panel or DIN rail

mounting screw at the analog I/O module end.

(1)

Keep shield

connection to ground as short as possible.

• If multiple power supplies are used with analog inputs, the

power supply commons must be connected.

• The modules do not provide loop power for analog inputs. Use

a Class 2 power supply that matches the input transmitter

specifications.

• Voltages on IN+ terminals of the modules must be within

±10V DC of module common (COM).

Effect of Transducer/Sensor and Cable Length Impedance on

Voltage Input Accuracy

For voltage inputs, the length of the cable used between the

transducer/sensor and the module can affect the accuracy of the data

provided by the module.

(1) In environments where high-frequency noise may be present, it may be necessary to directly ground cable

shields to earth at the module end and via a 0.1µF capacitor at the sensor end.

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Rockwell-automation 1769-IF16V Compact High Density Analog Input Modul Instrukcja Użytkownika Strona 21