Sentry IT Retrofit

SMC's industry-leading fire and gas solution.

Modernize Your Facility's Infrastructure

Sierra Monitor's Sentry gas detection solutions have long been the technology of choice for facility managers. With a reputation for innovation and reliability, Sentry solutions have been installed in tens of thousands of facilities that face potential risks from combustible and toxic gases.

However, the diligent facility manager knows that to stay “state-of-the-art," they must periodically refresh the technology deployed on site. New advances in sensing algorithms, protocols, web technologies, and cloud connectivity have the potential to enhance safety, reduce ongoing operational costs, and provide new big-data driven insights.

Gas Detection Controllers
1. Keep installed detector modules

No need for new wires

2. More channels

Additional input and output capacity

3. Minimal downtime

Keep your plant operational

4. Easy interface to virtually any SCADA or Building Management System

Included in the basic product

5. Web and cloud enabled

For easy-to-access and easy-to-view dashboards and reports


AC Version: 120/240 VAC +/- 10%, 50/60 Hz

DC Version: 24 VDC Nominal (18-30 VDC)

Power consumption: Controller 50W, Typical max system 200W

Battery Backup capability: External option


Operating Temperature: -14°F to 131°F (-10°C to 55°C)

Storage Temperature: -4°F to 140°F (-20°C to 60°C)

Relative Humidity: 0-95% Non-condensing


Type: 5.7" color, backlit touch-screen

Environmental rating: NEMA 4

Views: Bar charts, text data screens, configuration screens

Other Indicators: Integral long-life, high-intensity LED lights for Safe, Warning, Alarm, and Trouble

Connectivity to external controls and systems

Controller to Ethernet: Modbus TCP or AllenBradley Ethernet/IP (other protocols available)

Optional - Remote management: Web browser interface

Optional - Mass storage: Flash drive via USB port

Connectivity to modules

Channels: Up to 32 module addresses

Channel power: 24 VDC


  • Analong 4-20 mA: 2, 3, or 4-wire per ISA specifications
  • Modbus RTU (Sentry IT): RS-485 (half-duplex)
    • Baud: 38400 baud (adjustable 2400 - 38400)
    • Parity: None
    • Stop bit: 1
    • Data bits: 8
    • Flow control: None
  • SentryBus: Proprietary Power, Signal, Ground (PSG)
  • Binary Input: Supervised or Digital Input

4-20 mA: Variable retransmission 3-wire or 4-wire

Relay: Programmable, SPDT (multiples of 8)

Standard: 5 Amps

Optional: 8 Amps

Trouble: 5 Amps, Fail-safe


Design: Wall-mount


2 years

Sentry IT Fire and Gas Detection Solutions

A brief introduction to the sales, design and manufacturing facilities for Sierra Monitor Corporation's Sentry IT fire and gas solutions.

How to Easily Calibrate Sentry IT Gas Sensors with GlobalCal

A video demonstration on how to perform GlobalCal, the simple and time-saving calibration procedure, on all Sentry IT gas sensor modules.

Sentry NEMA Retrofit

A step-by-step walkthrough video on how to retrofit a Classic Sentry controller.