CONNECTING THE PAC S-SERIES CONTROLLERS
SNAP PAC Redundancy Option User’s Guide
10
Connecting SNAP-PAC-S2 Controllers
See also
“Wiring the 7-pin Serial Connector on SNAP-PAC-S2 Controllers” on page
and
the 6-pin Serial Connector on the Arbiter” on page
1.
Using ENET 2 on both controllers, connect the controllers to each other with a crossover cable.
To network
Crossover cable
ENET 2
ENET 1
NOTE: While not recommended, you can instead use a straight through cable to connect each
controller’s ENET 2 to your control network.
2.
Using ENET 1, connect the controllers to the network.
3.
Connect Serial 2 on Controller 1 to CTR1 on the arbiter using RS-485, “2-wire” mode.
4.
Connect Serial 2 on Controller 2 to CTR2 on the arbiter using RS-485, “2-wire” mode.
Arbiter
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.
CTR1
Common
TX/RX –
TX/RX +
Red + Black –
Pin 1
Common
TX/RX –
TX/RX +
Chassis GND
Controller
Serial 2
Arbiter
CTR1 and CTR2
Controller
ENET 2
ENET 1
Serial 2
