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Rockwell Automation Publication 1790-UM001B-EN-P - April 2021
Appendix A Install, Wire, and Configure PROFIBUS Modules
Guidelines for Output Modules
•
Current outputs (CH0 and CH1) of the 1790P-TNOC2 module source
current that returns to COM. Load resistance for a current output
channel must remain 0...600
.
Wiring the Modules
After the analog module is properly installed, follow the wiring procedure. To
ensure proper operation and high immunity to electrical noise, always use
Belden 8761 (shielded, twisted-pair) or equivalent wire.
To wire your module, follow these steps.
1. At each end of the cable, strip some casing to expose the individual wires.
2. Trim the signal wires to 5 cm (2 in.) lengths. Strip about 5 mm (3/16 in.) of
insulation away to expose the end of the wire.
3. At one end of the cable, twist the drain wire and foil shield together.
Under normal conditions, this drain wire and shield junction must be
connected to earth ground, via a panel or DIN rail mounting screw at the
analog I/O module end. Keep the length of the drain wire as short as
possible.
In environments where high frequency noise is present, ground the cable
shields to earth at the module and via a 0.1 μF capacitor at the sensor end
for analog inputs and at the load end for analog outputs.
4. At the other end of the cable, cut the drain wire and foil shield back to the
cable.
5. Connect the signal wires to the terminal block as shown in
6. Connect the other end of the cable to the analog input or output device.
7. Repeat steps 1...5 for each channel on the module.
ATTENTION:
To prevent shock hazard, care should be taken when
wiring the module to analog signal sources. Before wiring any analog
module, disconnect power from the system power supply and from
any other source to the analog module.
ATTENTION:
Never connect a voltage or current source to an analog
output channel.
ATTENTION:
Be careful when stripping wires. Wire fragments that fall
into a module could cause damage at power-up.
Cable
Cut foil shield and
drain wire
Signal wire
Signal wire
Drain wire
Foil shield
Signal wire
Signal wire
