Control Network Newsletter
Cost-effective Configurable I/O Modules for BACnet and Modbus
The need to expand the number of I/O points for an existing installation often arises in the field. Configurable I/O modules provide a cost-effective method to add devices and sensors with their available analog and digital inputs/outputs in varying combinations. The configurable I/O modules support two of the most popular communication protocols: Modbus (ASCII, RTU, TCP/IP) and BACnet (MS/TP, IP). By providing support for these open communication standards, configurable I/O modules provide solutions to both new and existing Building Management Systems (BMS). Modbus or BACnet operation is easily selectable with a dipswitch.
The configurable I/O modules provide universal inputs that support temperature, analog, resistance and binary in a single module. For applications not requiring universal inputs, modules with discrete inputs that support contact closure and retentive pulse counting at 100 Hz are available. Additional modules supply a mix of universal and/or discrete inputs with relay outputs and analog outputs.
The configurability of choosing the IO type and protocol at the site with the same module provides flexibility at the job site. A single module can support the various input types and may have some outputs like contact closure, or analog 0 to 10 VDC at 20 mA. Because of this flexibility, a single module may be able to handle the points at a single location. Analog Outputs on the modules can be used to trigger relays in applications to control higher voltage or higher current applications.
With typical I/O modules, a point just signals an on/off condition. The I/O on the Configurable modules have an accumulator function that can be used as a high-speed counter (up to 100 Hz) with the value being retained during a power failure. The accumulator function can also be used to count the number of times the input has been turned on. This can be used as an inexpensive way to monitor the operation cycle count for a piece of equipment.
A free software application for doing configuration, firmware updates and diagnostics on the configurable I/O is available. The software provides communication with the module over USB, BACnet MS/TP, Modbus RTU, BACnet IP or Modbus TCP. It allows monitoring the device's operating parameters, remote change of I/O module output states and input modes. This simple and intuitive software is a convenient tool for every configurable I/O user. Contemporary Controls provides an introduction video to the software to show users how to perform configuration, firmware updates and diagnostics on the configurable I/O modules.
To learn more, visit the I/O modules page.