Publication 20D-UM002C-EN-P - November 2003
Communicating with Devices on a DH-485 Link 10-9
Grounding and terminating a DH-485 network
You must terminate the network at the first and last PHYSICAL devices, by
connecting pin 6 (Termination) to pin 5 (Data A).
You must ground the network at the first PHYSICAL device by connecting
pin 1 (Chassis Ground) to pin 2 (Shield).
Example: DriveLogix
Controller, ControlLogix
Controller, and SLC
Controller on the Same
DH-485 Network
In the following example, both a DriveLogix controller and a ControlLogix
controller use its own 1761-NET-IAC+ converter to connect to a DH-485
Termination
Data A
Data B
Common
Shield
Chassis Ground
WH/OR
OR/WH
BU
6
5
4
3
2
1
Termination
Data A
Data B
Common
Shield
Chassis Ground
WH/OR
OR/WH
BU
6
5
4
3
2
1
Add jumpers to connect pin 6 (Termination) to
pin 5 (Data A) on the first and last PHYSICAL devices
Add jumper to connect pin 1 (Chassis Ground) to
pin 2 (Shield) on the first PHYSICAL device
IMPORTANT
A device’s physical location may be independent of its node
address. Make sure you ground and terminate the proper
PHYSICAL locations.
