MSA SENTRY io User Manual

2 Overview
US SENTRY io 11
Digital Inputs
The SENTRY io also supports connection to discrete dry contact (on/off) input devices. These inputs are 24 VDC input
signals. The wiring termination blocks for discrete input device connections are located to the right of the 4-20 mA signal
input terminal blocks and utilize a two-tier terminal block. The SENTRY io enables the internal 24 VDC power to be used for
the discrete 24 VDC signal inputs. See the figures below for location and typical wiring connection.
NOTE: Input 1/9 is pre-programmed for Remote Silence and input 2/10 is pre-programmed for Remote Reset. The balance
of discrete inputs are user configurable in the SmartStart configuration wizard.
2.3.3 Output Devices Compatibility
The SENTRY io provides relay contact outputs for energizing external devices and equipment when an alarm or fault
condition is identified. The SENTRY io relay contact outputs can switch either 24 VDC provided by the internal power
supply or from a user-supplied external power source. See the figure below to identify dry and wetted/powered pre-wired
contacts:
Module 1, relays 1-4 are dry contacts.

MSA SENTRY io Specifications

General

Brand	MSA
Model	SENTRY io
Category	Controller
Language	English