Technical Reprint TR-001
Sierra Monitor Corp. 1991 Tarob Ct., Milpitas, California 95035 USA 408-262-6611, 800-727-4377 FAX: 408-262-9042
Visit our Web Site at: http://www.sierramonitor.com E-Mail:
DCS software in conjunction with Sentry provides the operator enhanced data acquisition, alarming and alarm
management, historical trending, distributed architecture, and integration into the plant's distributed control system.
Sentry's MODBUS communication interface provides over 620 different parameters accessible by the PC-based
DCS software, including:
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Gas concentration
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Alarm setpoints
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Sensor diagnostic messages
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Historical reset time/date
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Power up/down time/dale trouble alarm time/date
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Minimum/maximum values plus time/date
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High/low alarm latch/non-latched
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Auto calibration enabled
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Calibration status/coefficients
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Calibration concentrations
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Calibration due date
•
Zone option enabled
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Operate mode
With the MODBUS communications option for Sentry and the graphic based man-machine software program a
variety of graphic screens can be developed. These screens make it easy for the operator to efficiently monitor haz-
ardous gas risks in any plant. Typically the system will include a main screen providing an overall view of the plant.
This screen is linked to individual zone displays, historical and real-time trend charts, bar charts indicating gas
concentration and alarm levels, and more.
SUMMARY
The key to any plant-wide monitoring system is the flexibility to configure system inputs/outputs and data
acquisition to meet the specific needs of the plant. By monitoring sensors throughout the plant, better visibility of
the ambient environment can be realized and more informed decisions can be managed in the event of gas exposure.
A plant-wide monitoring system using distributed intelligence coupled with advanced PC based software offers an
improved approach to limit in plant risks. The benefits to employee safety and environmental responsibility are
self-evident, as are the economic rewards of reducing the chance of loss from interruptions in operation and from
litigation. Risk minimization, including plant-wide gas monitoring, makes good business and social sense.
