Moore Industries International Inc. published Aug. 20 its latest whitepaper, “Closer to the process: uncovering the hidden benefits of utilizing remote I/O in process control systems”.

The whitepaper reports that field devices, such as temperature sensors, pressure transmitters, flowmeters and valve position switches, generate signals their control system needs to read. However, because industrial facilities spread across wide geographic areas, they face steep costs when connecting field instruments back to the control room or marshalling cabinet because each signal traditionally requires its own dedicated wire run, conduit and termination.

It adds that remote input/output (I/O) offers a practical, cost-effective alternative by digitizing field signals at the source, and carrying them back over one communications link, whether it’s copper, fiber, Ethernet or wireless. This approach eliminates the need for long, costly runs of dedicated field wiring and dozens of analog input cards for basic process control systems (BPCS). It also reduces wiring costs, speeds installation, enables maintenance, and makes it easy to add I/O points to aging systems, hazardous areas and remote locations without new control room hardware.

The types of signals remote I/O systems can handle include:

• Analog inputs and outputs with varying voltage and current signals, including 4-20mA current loop signals that are used by most industrial instruments;
• Discrete (digital) inputs and outputs, and on/off signals from switches, relays and solenoids; and
• Temperature inputs, thermocouple (TC) and resistance temperature detector (RTD) signals.