Western Reserve Controls 1782-JDO Manual de usuario descargar pdf (Pagina 18)

Western Reserve Controls, Inc. 1782-JDC User’s Manual

o 121 ohm

o 1% metal film

o 1/4 Watt

An appropriate terminating resistor, WRC part number RM121DN, may be purchased from

WRC.

IMPORTANT:

Per the DeviceNet spec -- do not terminate devices on drop lines.

4.4.2 DeviceNet Connection Wiring

The JDC uses a 5-pin plug-style DeviceNet connector, which has male pins.

Figure 4-2 DeviceNet cable connector

4.4.3 RS485 Network Termination (1782-JDC-2, 1782-JDC-4)

It is common practice to terminate an RS485 network system at each end of the serial cable

to eliminate electrical reflections. An appropriate value for the terminating resistor typically is:

• 100-120 ohm, depending upon the characteristic impedance of the cable used

o 121 ohms (same value as the DeviceNet terminator) is a standard resistor value

that may be used in many cases

• 1% metal film

• 1/4 Watt

Correct cable termination is the responsibility of the user. The 1782-JDC-2 does not include

an internal terminating resistor.

Note: 1782-JDC-2 products shipped with date code “0338” and earlier may have an internal

220-ohm terminating resistor installed. If you have any questions about this, please contact

WRC by phone or at support@wrcakron.com.

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Western Reserve Controls 1782-JDO Manual de usuario Pagina 18