
925-0301 Rev C
9
3.2 Connections and Wiring
A minimum configuration will require a three-wire power connection and a three-wire RS-485 connection
to the SmartBob network. Optionally, there may be a two-wire 4-20mA connection, a two-wire external
start connection and another three-wire RS-485 connection for the Expansion network.
All wiring is fed through water-tight cordgrips and connected inside the lower wiring cabinet to pluggable
terminal blocks mounted on the printed circuit board. Remove the two screws on the lower wiring cabinet
cover to gain access to the terminal blocks. When wiring is complete, be sure that the lid is properly
fastened down for a water and dust-tight seal. Never remove or unscrew the nameplate lid with the
keypad and LCD window.
There are a total of five terminal blocks but only four cordgrip/entry points inside the wiring cabinet. It is
recommended that if all terminal blocks are being used, that the 4-20mA Output (CN3) and the External
Start Input (CN4) share the same cordgrip/entry point.
All five terminal blocks are capable of supporting 22 to 12 AWG size wires. Be sure to use the
appropriate wire gauge/size for the connections and follow all national and local codes concerning this
installation.
3.2.1 Power Connection
The power connection (CN8) is a three wire terminal block located on the far right. Two terminal screws
marked + and – are for connecting to a 24VDC source, isolated from earth ground. See section 2.0
Specifications for power source requirements. Due to the low power requirements of this console, a 16 or
18 AWG wire would be sufficient for these two power connections.
The terminal screw marked with the
symbol should be connected to a quality earth for proper
protection from lightning and other electrical surges induced in an industrial environment. It is
recommended to use a 16 AWG wire or larger for the earth connection and connect it to the closest
possible source to earth.
It is recommended to use a separate isolated power source for every device on a SmartBob system. This
will provide additional protection from lightning and other electrical surges.
All three connections at CN8 are required for proper operation and protection of the console.