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The
Series 3000SGT Photohelic® Switch/Gage/Transmitter combines
several critical control functions into a single, easy-to-install
package. This versatile instrument starts with the universally accepted
standard for reliable low air pressure measurement, the Dwyer Magnehelic®
Gage. It measures positive, negative or differential pressures within
±2% of full scale accuracy. This time-proven component provides
highly legible analog indication of air or compatible gas pressure
on a 4", 80° scale. Gage operation is completely independent - functions
normally even if power is interrupted to electrical elements of
the control.
Next,
two DPDT relays are added which serve as Low/High limit controls
(or pressure switches) capable of handling up to 10 amps @ 24 VDC
or 120 VAC directly. Individual setpoint deadband is one pointer
width - less than 1% of full scale; just enough to assure positive,
chatter-free operation. Integral holding coils enable user to connect
the two so they work like a single control with variable deadband
- ideal for applications such as clean room and building pressurization,
HVAC systems, automatic air filter or level control and much more.
Actuation points are fully adjustable over the entire pressure range
with convenient from mounted knobs linked to bright red setpoint
indicators.
Finally,
the Photohelic® SGT includes a separate 4-20 mA, 2-wire
transmitter operating from an external 10.0-35 VDC power supply.
Separate adjustments are included for zero and span inside the rear
electronics enclosure. Optional A-700 Power Supply is a perfect
companion rated for AC inputs from 100-240V; DC outputs from 24
- 28V. The transmitter component is an ideal driver for variable
speed blowers and fans, damper positioners and for continuous data
logging on computerized VAV systems or strip chart recorders.
Besides
the obvious cost and space saving advantages of combining all these
control functions in a single unit, think of the additional savings
in time and material with just one set of pneumatic lines to connect
instead of three or four.
PHYSICAL
DATA
Ambient Temperature Range: 20 to 120°F (6.7 to 49°C)
Maximum Pressure: 25 PSIG (1.7 bar); Model No's 3020SGT &
3030SGT - 11 psi (75 kPa); all other units 5 psi (35 kPa)
Accuracy: ±2% of full scale at 70°F (21.1°C) (3% on -0)
Pressure Connections: 1/8" NPT(F)
Case Finish: Dark gray
Conduit Opening: ¾"
Standard Accessories: (2) 3/16" tubing to 1/8"
NPT brass adapters for rubber or vinyl tubing, (1) mounting ring,
(1) snap ring, (4) 6 - 32 x 2" mounting screws, instructions
Compatibility: Use only with air or other non-combustible,
non-corrosive gases
Weight: 4 lbs., 12 oz. (2.15 kg)
ELECTRICAL SPECIFICATIONS (Switches)
Power Supply: 117 VAC
Current Consumption: 5 watts average
Contact Rating: 10A @ 24 VDC or 120 VAC, 6A @ 240 VAC
ELECTRICAL SPECIFICATIONS (Transmitter)
Power Supply: 10.0 to 35 VDC
Output Signal: 4-20 mA DC, 2-wire (limited at 38 mA)
Loop Resistance: 0 - 1250 ohms
Current Consumption: 38 mA DC, maximum
Span and Zero Adjustment: Multi-turn potentiometers, internally
accessible
Thermal Errors: ±1% per 50°F typical
Warm-up Time: 10 minutes
OPTIONS
AND ACCESSORIES
Tamper-Proof Knobs: Require special spanner-type key (included)
to adjust set points. Add suffix -TAMP
A-700 Power Supply: AC input: 100/120/220/230-240 VAC ±10%,
47-63Hz. DC output: 24-28 VDC regulated
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