Looking for a reliable electronic switch
for your Safety Instrumented System?
The ONE Series Electronic Pressure and Temperature Switch with diagnostics is the ideal solution.
Simplify your Safety Shutdown Requirements with the One
Series Pressure and Temperature Switches:
• Reliable On-Off Digital Shutdown Signal
• Mount in field where direct and immediate shutdown is required
• Improve reliability while simplifying wiring and software
• Use in 2 of 3 voting logic schemes
exida, L.L.C. has completed a Failure Modes, Effects and Diagnostic
Analysis (FMEDA) and report for UE’s One Series Electronic Switch
line. The report is available to engineers who are designing Safety
Instrumented Systems (SIS), providing test data to calculate the Safety
Integrity Level (SIL) of a system containing the One Series. The FMEDA
from the exida report includes:
• The One Series has a safe failure fraction
between 60% and 90% for SIL 1 applications
as a stand-alone pressure or temperature
sensing electronic switch.
SIL
Safety Integrity Level for a stand-alone
One Series
PDFavg
Average Probability of Failures on
Demand
SFF
Safe Failure Fractions summarize the
fraction of failures
• The One Series has an estimated useful
lifetime of 50 years.
Failures in Time
• This data is to be considered in combination
with other devices when determining
suitability for a specific safety integrity level
(SIL).
FIT
HFT
Hardware Fault Tolerances
The One Series is classified as a Type B device,
using micro controllers and programmable logic.
The One Series is a predictable fail-safe-open switch
categorized as a self-diagnostic smart device that
senses temperature or pressure and provides discrete
and 4-20 mA outputs.
The intelligent and self-diagnostic One Series
Electronic Switch is ideal for SIS applications.
For more information on the
FMEDA report or the One
Series electronic pressure and
temperature switches, please
contact UE at (617) 926-1000
or visit us at
www.UEonline.com
ADDITIONAL INFORMATION
exida is one of the world’s leading companies specializing in automation system safety,
maintaining a comprehensive failure rate and failure mode database on process equipment.
United Electric’s One Series Electronic Switch is a self-diagnostic smart device classified as
a Type B device with a SFF between 60% and 90% and suitable for SIL 1 applications with an estimated
useful lifetime of 50 years. The One Series senses temperature, pressure and differential pressure and
provides discrete on-off outputs. The One Series is classified as a Type B device, according to IEC 61508,
using micro controllers and programmable logic. The FMEDA shows that the One Series is suitable for SIL 1
applications.
· FMEDA - Failure Modes, Effects and Diagnostics Analysis: The report summarizes the results of the hardware
assessment of the One Series Electronic Switch. The FMEDA is a major step toward achieving functional
safety certification per IEC 61508, providing failure rates and Safe Failure Fractions (SFF) for the electronic
and mechanical systems found in the One Series design.
· IEC 61508 - International Electrotechnical Commission functional safety standard for risk reduction.
· SFF - Safe Failure Fraction summarizes the fraction of failures, which lead to a safe state of the fraction of
failures, which will be detected by diagnostic measures and lead to a defined safety action.
· Type B Device - The One Series is a complex component using micro controllers and programmable logic
according to IEC 61508.
· SIL 1 - Safety Integrity Level 1 provides minor property and production protection with a probability of
failure of 10-1 to 10-2. The One Series may be used up to SIL 1 as a single device.
For access to the report, please contact Rick Frauton at (617) 321-1231 or by email at
rfrauton@ueonline.com.
United Electric Controls is an ISO 9001 certified lean manufacturer of the One Series and
leader in the design and application of Threshold Detection and Switching technology.