I/O Sentinel® 4 G2 – Web-based GPIO Interface

The I/O Sentinel® 4 G2 is a robust, full-featured Ethernet based data acquisition and remote-control device with four optically isolated status (logic) inputs and four programmable relays. The I/O Sentinel® 4 G2’s four optically isolated status/logic inputs may be configured for wet or dry (contact closure) status/logic monitoring. The four one-amp SPDT relay outputs may be configured for ON, OFF, pulsed or reboot operation.


The I/O Sentinel® 4 G2 can be controlled and monitored locally and/or remotely over any IP network, including private networks, IP-based industrial control networks, and the Internet. Users can operate the product using a web browser or web-enabled mobile device. Email notification may be configured to alert up to eight email or SMS-email addresses. Logging of system status, along with the site ID may be emailed in time spans from once an hour to once a day. SNMP traps and SET/GET to allow multiple units to be monitored and controlled with SNMP management software.

The I/O Sentinel® 4 G2 may be paired with a second I/O Sentinel® 4 G2 to form an IP-based “4 Channel Bi-directional Status/Relay Extension Cord”.


  • • Four optically isolated inputs configurable for dry signals or wet signals (5-24 VDC, or 25-48 VDC via an external resistor.)
  • • Four SPDT relay outputs.
  • • Plug-in euro-block screw terminals for status and relay connections.
  • • Built-in web server provides simple, web-based (HTML5) notification, monitoring, configuration, and control.
  • • Email and SMS-email alarm notification for input, outputs, and logs.
  • • Remote control and monitoring via SNMP GET/SET and traps.
  • • Logging of all user selected input status with site ID information which may be emailed from once an hour to once a day, along with hourly snap-shot functionality.
  • • Nine front panel I/O activity LED indicators.
  • • Rear panel RJ-45, 10/100base-T LAN/Ethernet interface.
  • • Fully RFI proofed.
  • • Surge protected power supply.  Domestic power supply provided.
  • • Three units may be mounted on one RA-1 one-RU 19” rack shelf.


  • • Web-enabled back-up transmitter ON/OFF control system.
  • • One end of a full-duplex four channel web-enabled I/O extension cord.
  • • Relay control and status monitoring via a web browser and/or user defined PC application.