Controller
Serial 2
ENET 2
ENET 1
Arbiter
CTR2
CTR1
Common
TX/RX –
TX/RX +
Red + Black –
Pin 1
Common
TX/RX –
TX/RX +
Chassis GND
Controller
Serial 2
Arbiter
CTR1 and CTR2
NOTES on RS-485, “2-wire” mode:
• Correct RS-485 “2-wire” mode requires a single
twisted pair for the data wires and an additional
insulated wire for the signal common connection.
• It is usually easiest to use a two-pair (shielded) RS-485
data cable, as follows:
- One pair for data
- One pair for signal common
- Shield for chassis ground.
• Do NOT connect the signal common to chassis
ground.
CONNECTING THE PAC S-SERIES CONTROLLERS
SNAP PAC Redundancy Option User’s Guide
12