NI Remote I/O is a low-cost, modular I/O system for simple machine control and measurements. Remote I/O can be used to round out a system with low-cost I/O for simple tasks while the controller handles advanced tasks such as image processing, motion control, and high-speed or specialty measurements.
Remote I/O is a low-cost, modular system used for simple tasks while a controller handles advanced tasks such as image processing, motion control, and high-speed or specialty measurements. You may have also heard this form factor called block or slice I/O.
Remote I/O is generally installed in a cabinet. Depending on your I/O needs and how distributed your system is, your remote I/O system will likely be installed either in the same cabinet as your controller or in a separate cabinet located near your I/O point. In both cases, the remote I/O system is controlled from an NI real-time controller connected via EtherCAT (Figure 2).
Figure 1. Common system configurations for remote I/O are (A) installed in a central control cabinet next to your controller and (B) installed in a cabinet near the I/O.
Often, advanced control or measurement systems have two categories of I/O – (1) high-speed, high-precision, high-accuracy, or specialty measurements, and (2) basic, slow I/O. The first category can be addressed with C Series I/O modules. The second category can be addressed with C Series or remote I/O modules. Each of these I/O options has its strengths (Table 1).
Table 1. A comparison of different I/O options offered by NI.
A minimum remote I/O system includes an EtherCAT bus coupler and a single I/O module, mounted on a DIN rail. Remote I/O modules are programmed and controlled from an NI EtherCAT master such as a CompactRIO Controller or Industrial Controller. A full list of supported controllers can be found here.
Figure 2. NI Remote I/O system showing EtherCAT bus coupler, modules,and bus connectors.
There are a variety of I/O modules for remote I/O including temperature input, analog input and output, and digital input and output. You can browse a full list of modules here.
Remote I/O requires the following software:
• LabVIEW 2016 or later
• LabVIEW 2016 Real-Time Module or later
• NI Industrial Communications for EtherCAT 16.0 or later
NI Remote I/O well integrated with LabVIEW and is programmed using a combination of configuration VIs and I/O nodes. These VIs are added to a LabVIEW palette by the NI Industrial Communications for EtherCAT driver. Example code for analog and digital I/O is shown below.
Figure 3. Remote I/O is programmed with a combination of configuration VIs and I/O nodes for a seamless programming experience.
Remote I/O modules can be auto-discovered in the project and will show up in the LabVIEW Project Explorer under your EtherCAT master.