Emerson Rosemount 928 Quick Start Manual page 78

Quick Start Guide
Initiate action (for example, close valves, initiate facility evacuation, call

emergency services)
If installing an optional, customer-supplied external alarm device, verify proper function.

Verify that gas concentrations in the area have dissipated to a safe level before clearing local or digital

alarms.
When connecting an external device to the Rosemount 928 Wireless Gas Monitor's discrete output in a

hazardous area, ensure that the external device is installed in accordance with Intrinsically Safe or
non-incendive field wiring practices.
The Rosemount 928 Wireless Gas Monitor does not need to be connected to a wireless network for the

external alarm device to function. However, the low battery, no measurement, or sensor failure alerts will
not be available.
There are two possible connection methods for the external alarm device:
Four-wire: This connection method (most common) uses a set of two wires

for an IS input power supply. Another set of two input wires is used for a
separate IS alarm mechanism.
Two-wire: This connection method combines an IS power source, such as an

internal battery, and an alarm device into one package.
An optional, customer-supplied alarm suppression button may also be added.
14.1 Connecting an external alarm device
1. On the Rosemount
rear housing cover to expose the terminal block.
A. +Barrier Power
B. -Barrier Power
C. +Output to Alarm
D. -Output to Alarm
E. +Comm Terminal
F. -Comm Terminal
2. On the Rosemount 928 Wireless Gas Monitor main housing, remove one of
the conduit plugs.
78
™ 928 Wireless Gas Monitor main housing, remove the
August 2018