B&B Electronics 3PCIU4 User Manual
Page 72
RS-422/485 Connections/Operation
66
Chapter 8
Manual Documentation Number 3PCIoUx-1008
3. Connect the RD(B) pin #9 on the computer to TD(B) on the device.
4. Connect the RD(A) pin #1 on the computer to TD(A) on the device.
5. Connect the Signal Ground pin #5 to Signal Ground on the device.
RS-422 Point to Multipoints Connection
In a multi-slave RS-422 connection, TD(B) and TD(A) connect to RD(B) and
RD(A) on all the slaves. If the slaves have Transmit connections, only one
device can be connected back to the master.
Figure 50. RS-422 Master to RS-422 Receive Only Devices
4-Wire RS-485 Connection
In a 4-wire RS-485 system, each receive line connects to the same receive
terminal on all slaves, and each transmit line connects to the same transmit
terminal on all slaves. The master to the first slave is connected as above.