Installation Requirements
Before you install the module, you must complete these steps.
1. Install a 1756 ControlLogix chassis.
2. Install a 1756 ControlLogix power supply.
Install the Module
You can install or remove a module while chassis power is applied.
Slide the module into the slot in the chassis until the locking tabs click.
Key the Removable Terminal Block
Key the RTB to help prevent inadvertently connecting the incorrect RTB to your
module.
1. Push the U-shaped band onto the module until the band snaps into place.
2. Insert wedge-shaped tabs into positions on the RTB that correspond to
unkeyed module positions on the module until they stop.
Connect Wiring
You can use an RTB or a Bulletin 1492 prewired interface module (IFM) to connect
wires to your module.
If you’re using an RTB, see Recommendations for Wiring Your RTB, to connect wires
to the RTB. IFMs are prewired before shipping.
Wire a Cage Clamp-style RTB
3. Insert the wire into the terminal.
4. Turn the screw clockwise to close the terminal on the wire.
Wire a Spring Clamp
1. Insert the screwdriver into the outer hole of the RTB.
2. Insert the wire into the open terminal and remove the screwdriver.
Recommendations for Wiring Your RTB
We recommend that you follow these guidelines when wiring your RTB:
• Begin wiring the RTB at the bottom terminals and move up.
• Use a tie to secure the wires in the strain relief (bottom) area of the RTB.
• Order and use an extended-depth housing (catalog number 1756-TBE) for
applications that require heavy gauge wiring.
ATTENTION: The module is designed to support removal and
insertion under power (RIUP). However, when you remove or
insert a removable terminal block (RTB) with field-side power
applied, unintended machine motion or loss of process control
can occur. Exercise extreme caution when using this feature.
We recommend that you remove field-side power before
installing the RTB onto the module.
SHOCK HAZARD: If the RTB is installed onto the module while
the field-side power is applied, the RTB is electrically live. Do
not touch the RTB terminals. Failure to observe this caution
can result in personal injury.
Locking Tab
U-shaped
Keying Band
Wedge-shaped
Keying Tab
WARNING: If you connect or disconnect wiring while the field-side
power is on, an electric arc can occur. This could cause an
explosion in hazardous location installations. Be sure that power
is removed or the area is nonhazardous before proceeding.
ATTENTION: If multiple power sources are used, do not exceed
the specified isolation voltage.
ATTENTION: When using the 1756-TBNH, do not wire more than
two 0.33...2.1 mm2 (22...14 AWG) conductors on any single
terminal. Use only the same size wires with no intermixing of
solid and stranded wire types.
When using the 1756-TBSH, do not wire more than one
conductor on any single terminal.
ATTENTION: The ControlLogix system has been agency
certified using only the ControlLogix RTBs (1756-TBNH and
1756-TBSH). Any application that requires agency certification
of the ControlLogix system using other wiring termination
methods may require application-specific approval by the
certifying agency
digital I/O modules are input and output modules that provide On/Off detection and actuation. By using the Producer/Consumer network model, digital I/O 
