Sentry Gas Detection System

The power of Sentry is in the various features and options that can be added to the basic system to provide a system designed for your specific application. Adding in external sensors from other suppliers, analog output signals, individual relay configuration, Modbus or other protocol output, remote display and relays are all available features found on a Sentry system.

Note: Move your mouse over various areas of the picture below to view information on some of these enhanced features. Click on the Basic Sentry System icon to the right of the graphic to view the Basic system.

Basic Sentry System

Sentry System

Multiplexing capability

In addition to the cost savings, multiplexing also makes it easier to install sensors a great distance from the controller. Using an optional external power supply for the sensors, two-wire communication is all that is needed to link from the remote site to the controller.

Multiple Analog Inputs

Should the user have multiple analog devices that need to be interfaced to their Sentry system, we offer the 5100-90 Analog Input Module where multiple devices can be connected.

Input from Other devices

The 5100-99 Single Channel Analog/Digital Converter enables the user to bring a 4-20 mA signal from a non-Sentry device into a Sentry system. This feature is ideal should the user need a special gas sensor, flame sensor or other device in their system

Addressable Output Module (AOM)

When the user needs to display the gas concentration and alarm status or to have relay contacts remote from the sensor and the controller, such as outside an enclosed space, the Addressable Output Module meets that need.

Sentry Controller

Various software enhancements are also available to provide the flexibility needed for many systems. Gas tags and module tags are available edited at the factory or by the user for easy identification of sensors. Enhanced alarm acknowledgement features enable the user to meet specific needs. Interface to the Sentry Commander provides a central alarm processing center.

Individual Relays

If separate relay action is required for each sensor then the Individual Relay Option is appropriate. This provides individual SPDT dry contact relays for each alarm level for all sensor modules. Alarm logic flexibility in Sentry will enable the user to set up various relay options including zone alarms.

Sentry Power

Besides standard 110 and 220 VAC power, check with your Sierra Monitor representative to learn about the various backup power supply systems available to keep your hazardous gas detection system operating even when line voltage power is lost.

Sentry Relay Logic for Customized Response

Standard are 3 relays on each Sentry Controller. Check out the individual relay options available for Sentry

Modbus Protocol and More

Sentry was the first ambient air monitoring system to offer Modbus RTU digital output to interface to plant distributed control systems, modems and other devices. Sentry now can also offer other protocols via the FieldServer gateway including DH+, EtherNet/IP, Modbus TCP, ControlNet, Profibus and many more!

Analog Output

Some systems need a 4-20 mA output signal from Sentry. For those applications we offer the Output Expansion Module that includes a 4-20mA signal for each of the 8 sensors, plus individual relays for each of the 8 sensors.

For more information