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SMC sierra monitor corporation Sentry Instruction Manual - Version 6
PRODUCT DESCRIPTION
Page: 1
1. PRODUCT DESCRIPTION
1.1 GENERAL
The Sentry 5000 is a fixed installation gas monitoring
system designed for continuous operation in open or
confined areas. The system is comprised of a controller
and up to eight sensor modules. The sensor modules are
supplied for detection of combustible gas, oxygen
deficiency or various toxic gases and can be mixed within
one system as required.
1.2 CONTROLLER
The Sentry controller is a microprocessor computer which
performs functions including management of the sensor
modules, management of alarm relays and interface with
the user via the front panel which includes a concentration
display, an alphanumeric display, keypad and status
indicators. The microprocessor functions are permanently
installed in the controller. They cannot be changed or
damaged by the user and will not be altered by loss of
power.
Configuration variables, such as alarm levels, can be
changed via a simple keypad sequence. Information
provided to the controller in this manner is retained even
when the power is interrupted. This information can be
protected by a "user code" to avoid unauthorized
modification.
Sentry continually scans all modules for alarm conditions.
No sequence of key presses can prevent the scanning
except specific actions during calibration or deliberate
disabling of the sensor module.
The Sentry controller is provided in a rack or panel mount
version for control rooms, an environmental enclosure for
outdoor, stand alone applications, or other packages for
specialty applications.
1.2.1 ENHANCEMENT PACKAGE
Various factory installed firmware enhancements are
available for the Sentry controller. These are selected at
the time of purchase or subsequent upgrade. The
enhancements, which are described in detail in the
appropriate sections of this manual, include:
− Addition of printer output firmware for models
5000-04 or 5000-02. Printer output is standard
on model 5000-08.
− Replace printer output firmware with MODBUS
data address protocol for host computer or DCS
interface. MODBUS is an industry standard
communication protocol which allows bi-
directional communication via the controller RS-
232C serial port.
− High Alarm Acknowledge function for alarm
reset.
− Low Alarm Acknowledge function for alarm
reset
− Emergency Alarm function adds a third alarm
level.
− Zone and Voting assignment of individual alarm
relays.
− Analog Output software driver for use with
Model 4314-01 output module.
− Custom default Gas Tags and Engineering Units
Tags for up to eight input devices.
− Custom default Module Tags for up to eight
module addresses.
− Configure alarm relays to be normally energized
in the safe condition.
1.3 SENSOR MODULES
Each sensor module ("module") is labeled internally to
identify the type of gas it is designed to detect. For each
gas group, the sensor and the electronics board in the
explosion proof housing is different. During installation,
switches in the electronics are set by the user to give the
module an address (module number) to make it unique
from others in the same system. Sentry then
"communicates" with each module to determine its
number, the type of gas it detects, the gas concentration
and other information.
Inside the module housing is an electronic assembly
consisting of two printed circuit board assemblies mounted
under a metal top plate. The address switches and
adjustment potentiometers are accessible through the plate
and electrical test points (test lead jacks) are installed in
the plate. Connectors for wiring from the controller and
the sensor are located on the bottom of the electronic
assembly. The sensor is installed in one hub of the
enclosure.