Rockwell Automation 1747-DSN DISTRIBUTED I/O SCANNER - Manual (Page 14)

Chapter 2
Wiring and Installation
2–2
The scanner and I/O blocks are connected to the DIO Link in a daisy chain
configuration. A daisy chain configuration is formed by connecting the
scanner and I/O blocks together in a serial manner along a single section of
link cable (Belden 9463). The scanner is attached to the DIO Link using its 3
position DIO Link connector, and the I/O blocks are attached to the DIO
Link using 3 terminals on their 6 position DIO connector.
There are no restrictions governing the spacing between each device, as long
as the overall length of the DIO Link does not exceed 2,500 feet. However,
no two devices may be connected to the same point on the DIO Link. 82 ohm
terminating resistors must be attached at each end of the link. A termination
kit is included with each scanner for this purpose. In addition, the DIO Link
cable shield must be earth grounded at one point on the link. Specific
attention should be paid to the DIO Link cable shield grounding, because this
must be coordinated with the grounding of the DH–485 Data Link shield.
Examples of correct and incorrect DIO Link configurations are shown below,
and specific wiring details are provided on the following page.
Terminating
Resistor
Incorrect
Terminating
Resistor
Correct
Terminating
Resistor
Terminating
Resistor
Incorrect
Correct
Terminating
Resistor
Terminating
Resistor
Terminating
Resistor
Terminating
Resistor
Wiring the DIO Link