SAF Series Air Velocity Switch
The solid state SAF Series airflow switch assures dependable thermal control and protec-
tion for air cooled systems. The SAF Series advantages include:
Can drive logic circuits, audible/optical alarms and magnetic relays
Available in sealed and dust-proof versions
Can be socket mounted, PCB or hard wired
Available in 50 to 1500 linear feet per minute ranges
Not affected by ambient temperatures
5 VDC design with low power dissipation
Signal conditioning not required
The advanced SAF Series Airflow Switch provides early detection and protection from overheating in high-end
computer systems and peripherals, large power supplies, HVAC equipment, medical diagnostic systems and other
electronic systems requiring forced air cooling.
The patented* design is based on a heated thermistor which monitors the airstream and detects a loss or
reduction of airflow due to fan failures, clogged filters or obstructions in the air inlet/outlet. The thermistor
temperature and, therefore, its resistance, is affected by changes in air velocity. The SAF thermistor is part of a
sensing bridge which compares its own resistance against a reference circuit and determines the air velocity at
which the device will trigger an output.
The innovative, low profile airflow sensor is easily mountable directly on the most densely populated circuit
boards with as little as .625 inch spacing between boards, in sockets or bracket mount in plenums. All SAF
models are complete, self-contained sensor/alarm devices requiring no additional circuitry.
*US Patent No. 4,686,450
All SAF Series Sensors are designed to be used in conjunction with typical logic circuitry. They
operate on a +5 VDC supply and their output provides an open collector NPN transistor with its
emitter connected to ground (0v). This type of versatile output allows driving logic circuits, indicat-
ing incandescent or LED lights or even magnetic relays, from DC sources from 5V to 30V.
Mounting Accessories
♦
Military Socket Assembly with leads, no
mounting bracket - P/N 4-1-261
♦
Bracket only, with leads attached to SAF
Sensor - P/N 4-1-270
♦
Socket Assembly with mounting bracket
and leads - P/N 4-1-260
IMPROVED AMBIENT TEMPERATURE
COMPENSATION
Warren G-V design criteria for the SAF
Solid-State Airflow Sensor incorporates
ambient temperature compensation
techniques which provide close operating
point tolerances over the ambient range
of +10° to +60°C. The typical operating
point versus ambient temperature curve
for 250 FPM is illustrated. Curves for
other settings are available.
SPECIFICATIONS
Input Voltage: +5 VDC (±5%)
Power Dissipation: ½w max
Output: open collector, solid
state, able to sink up to 100 MA
to ground, from DC sources up to
30V
Sensing range: 50 to 1500 F.P.M.
Sensing Tolerance: +10°C to
+60°C see ambient temperature
compensation curve
Sensitivity: ±25 F.P.M. from actual
setting
Hysteresis: Series SAF1005 (Stan-
dard Model) is typically 10% of
the setting
THE SAF SERIES
The Standard Series/SAF1005
- indicates an “alarm condi-
tion” on low or no airflow by turning output transistor “on”;
output is similar to a closed mechanical contact between
output and ground when in alarm condition. A round ver-
sion, SAF1006 without a flange is available for less board
space utilization.
The Fail Safe Series/SAF1025
- an alternative to above-
described series, a device failure indicates an “alarm condi-
tion” by turning the output “off”; similar to open contacts in
alarm condition. It will operate with a wider hysteresis.
The Hermetically Sealed Series
- withstands all board
washing methods; more suitable for applications with hostile
environments. Sealed versions of all the above units are
available.
Output on
Alarm Condition
Driving
A Load
(Relay, Lamp)
Logic
Interface
(Pull-up
Resistor)
ON
OFF
SAF Model Options
Dust Proof
Flanged
Round
Base
SAF1006
SAF1026
Hermetically Sealed
Flanged
Round
Base
SAF1008
SAF1028
ON
OFF
SAF1005
SAF1025
SAF1007
SAF1027
嵌入式系统
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