Rockwell Automation 1398-DDM-xxx USE MNL/ULTRA 200 DIG.SERVO.DR - Manual (Page 104)

Publication 1398-5.0 – October 1998
6-40 Interfaces
Four Wire RS-485 Connections
The ULTRA 200 Series drives use a variation of the RS-485 standard,
known as four wire RS-485. Four wire RS-485 uses one differential
signal for host to drive transmissions, and another differential signal
for drive to host transmissions. (The RS-485 standard specifies a
single differential signal for transmissions in both directions.)
The four wire RS-485 configuration also allows the host to use a RS-
422 type interface. Because the host is driving multiple receivers and
receiving from multiple transmitters, RS-422 is limited to multiple
axes connections with 10 or less drives. The figure below summarizes
the four wire RS-485, RS-422, and RS-485 standards.
Figure 6.40 RS-485/RS-422 Communication Comparison
Intro
Four Wire RS-485
Differential
4 Wires
2 Signal Pairs
1 to 32 Transmitters
1 to 32 Receivers
Intro
RS-422
Differential
4 Wires
2 Signal Pairs
1 Transmitter
1 to 10 Receivers
Intro
RS-485 Standard
Differential
2 Wires
1 Signal Pair
1 to 32 Transmitters
1 to 32 Receivers
NOTE: Not applicable to
ULTRA 200 Series drives
1 2 32
1 2 10
1 2 32