Series AT3  A3000

ATEX Approval Photohelic^® Switch/Gages with 120, 240 or 24 VAC Power

Photohelic^® Switch/Gages in Flame-Proof ATEX Enclosures

Flame-proof ATEX approved Photohelic^® Switch/Gages, Series AT3A3000, function as

versatile, highly repeatable pressure switches combined with a precise pressure gage employing

the time-proven Magnehelic^® gage design. The Photohelic^® switch/gage measures and controls

positive, negative or differential pressures of air and compatible gases. Standard models are rated

to 25 psig (1.7 bar) with options to 35 psig (2.4 bar) or 80 psig (5.5 bar). Two phototransistor

actuated, DPDT relays are included for low/high limit control. Easy to adjust set point indicators

are controlled by knobs located on the gage face (accessible opening case after de-energizing

instrument). Set points can be interlocked to provide variable dead band-ideal for control of fans,

dampers, etc. Gage reading is continuous and unaffected by switch operation, even during loss of

electrical power. Flame-proof ATEX enclosures are available in aluminum with glass window which

allows for viewing of set point needles and process pressure.

SPECIFICATIONS

Service:

Air and non-combustible, compatible gases.

Wetted Materials:

Consult factory.

Accuracy:

+/-2% of FS at 70^๐F (21.1^๐C);

+/-3% on -0 and +/-4% on -00 models.

Pressure Limits:

-20 in Hg to 25 psig (-0.677 to 1.72 bar).

MP option; 35 psig (2.41 bar), HP option; 80 psig (5.52 bar).

Temperature Limits:

20 to 120^๐F (-6.67 to 48.9^๐C) LT low temperature option to

-20^๐F available; Case: -58 to 140^๐F (-50 to 60^๐C)

(Note: Product temperature limits differ from case).

Dial Size:

4” (101.6 mm).

Mounting Orientation:

Diaphragm in vertical position.

Set Point Adjustment:

Adjustable knobs on Photohelic^® gage face behind enclosure cover. Follow instructions and safety warnings to open cover.

SWITCH SPECIFICATIONS

Switch Type:

Each setpoint has 2 Form C relays (DPDT).

Repeatability:

+/-1% of FS.

Electrical Rating:

10A @ 28 VDC, 10A @120, 240 VAC.

Electrical Wiring:

Screw terminals.

Power Requirements:

120 VAC, 50/60 Hz; 240 VAC & 24 VAC power optional.

Enclosure Rating:

IP66. IP65 with option OPV, overpressure relief valve.

Housing material:

Aluminum.

Finishing:

Texture epoxy coat RAL7038.

Pressure Connections:

1/8” NPT female brass (SS optional). In presence of acetylene    it is necessary to use SS.

Electrical Connections:

Three ½” FNPT. Cable gland not included.

Weight:

28.4 lb (12.9 kg).