The I/O wiring recommendations provide guidance on what type of wires should be used for the different I/O modules and the AS-B onboard I/O, how to perform grounding, and how to connect different external devices to the inputs and outputs. Always use the recommended cables and wires.
For the I/O modules, most of the wiring is made to the terminal base, and can be done before the electronics module is installed.
For the AS-B onboard I/O, the wiring is made to the removable terminal blocks, and can be done before AS-B is installed on the DIN rail.
For digital inputs and outputs, you can use shielded or unshielded wire. Unshielded wires are usually sufficient.
For analog inputs and outputs, you can use shielded or unshielded wire. Shielded wires are recommended if the wiring is placed in a noisy electrical environment. Connect the shield to ground only at a RET terminal.
If the wiring is placed in a noisy electrical environment, shielded wires are recommended for RTD-DI-16 I/O modules and AS-B onboard I/Os that have the following external connections:
RTD temperature input
RTD resistive input
Resistive input
It is important to perform the grounding correctly for the following reasons:
To design a safe system that is not harmed by minor connection errors.
To design a system that works well and is resistant to EMI.
To minimize the effects of ground currents that can cause unstable measurements.
For more information, see Grounding and Power .
There are many different kinds of external devices from different vendors that can be connected to a SmartStruxure solution.
For more information, see External Device Connections .