Dwyer Series 640 Air Velocity Transmitter
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Rugged
steel NEMA 13 housing with 12" stainless
steel probe on 6' connecting cable.
Liquid tight cable entrances. - Patent No. 4,860,583 |
The Dwyer Series 540
Air Velocity Transmitter is ideal for a wide range of HVAC
measurement and control applications, particularly in complete
building control and energy management systems. Designed
for use in reasonably clean and dry air streams, applications
include multi-point air velocity measurements, supply and
exhaust fan tracking, industrial hygiene and clean-room systems,
air pollution studies and manufacturing or process control
systems.
The Series 640 brings ±2% accuracy (including linearity,
hysteresis and repeatability) to these types of
demanding applications at a surprisingly
low cost. With four field selectable ranges of 0-200, 0-1000, 0-3000
and 0-12,000 FPM, this single transmitter can be supplied off-the-shelf
for a variety of different air velocity measurement applications.
The Series 640 transmitter is easily installed with the mounting hardware
supplied, including a split flange for securing the sensing probe in
the duct. Requiring only 18-24 volts AC or 22-29 volts DC for power and
having a two-wire, 4-20 mA output, electrical connections are made quickly
and easily by means of a four-wire cable to a plug-in terminal block
through a liquid tight cable gland. The NEMA 13 housing is suitable for
all indoor industrial, institutional or commercial installations, An
optional probe extension is available for larger duct sizes.
 The
central components o the Series 640 transmitter
are the velocity and temperature sensors located
int he tip of the probe. The velocity sensor is
a constant temperature thermistor which measures
the air velocity, referenced to standard conditions,
by sensing the cooling effect of the moving air
passing over the heated sensor. The power required
to maintain the velocity sensor temperature, as
provided by the control circuitry in the electronics
package, is a function of the air velocity. The
velocity sensor is rugged enough to tolerate particulate
contamination and still provide fast response to
changes in air velocity. A temperature sensor in
the probe tip compensates for a wide range of air
stream temperature variation. Each transmitter
is individually calibrated at our factory in a
computer controlled wind tunnel. During this calibration
procedure, the inherent non-linearity of the thermistor
velocity sensor is automatically corrected by appropriate
programming of an EPROM in a linearizer circuit
of the electronics package.
PHYSICAL
DATA
GENERAL
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| Media: |
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Air |
| Ranges: |
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0-200,
0-1000, 0-3000, 0-12,000
FPM (field selectable:
referenced to standard
conditions) |
ELECTRICAL
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| Power
Supply: |
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18-24
VAC, 22-28 VDC |
| Output
Signal: |
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4-20
mA DC |
| Loop
Resistance: |
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0-300
OHMS |
| Current
Consumption: |
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250
mA Maximum |
| Warm-up
Time: |
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3
to 5 minutes |
PERFORMANCE
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| Zero
Output: |
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4
mA |
| Full
Span Output: |
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20
mA |
| ACCURACY: |
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(%
of F.S.) |
| 0-200
fpm range |
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±5%
@ 32-180°F
±9% @ 0-32°F or 180-200°F
|
0-1000,
0-3000 or
0-12,000 fpm ranges |
|
±2%
@ 32-180°F
±6% @ 0-32 or 180-200°F |
ENVIRONMENTAL
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| Temperature
Ranges: |
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Operating,
-32 to 160°F
Storage, 0 to 200°F |
MECHANICAL
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| Weight: |
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3
lbs |
| Probe
length: |
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12
inches |
| Cable
length: |
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6
feet |
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