The Photohelic
®
Switch/Gage is a very versatile, precise
pressure switch combined with the time-proven
Magnehelic
®
pressure gage. Models are available with one
or two phototransistor actuated relays. Gage reading is
unaffected by switch operation. Easy to adjust set points
have knob controls. Applied pressure and switch set points
are fully visible at all times. Deadband is one pointer width -
less than 1% of full scale. Double-pole double-throw relays
can be easily interlocked to provide variable deadband con-
trol. For positive, negative or differential pressure only on
3600S models. Full scale ranges available from 0-.25 in w.c.
to 0-6000 psig.
PHOTOHELIC
®
SENSING - HOW IT WORKS
In a typical control application, the Photohelic
®
switch/gage
controls between high and low pressure set points. When
pressure changes, reaching either set point pressure, the
beam from an LED to the limiting phototransistor will be cut
off by the helix-driven light shield. The resulting signal
change is electronically amplified to actuate its DPDT slave
relay and switching occurs. Dead band between make and
break is 1% of full scale or less - just enough to assure pos-
itive, chatter-free operation.
SPECIFICATIONS
GAGE SPECIFICATIONS
Service: Air and non-combustible, compatible gases.
Wetted Materials: Consult Factory.
Accuracy: Photohelic
®
, ±2% of full scale at 70°F (21.1°C). ±3%
on -0 and ±4% on -00 models.
Pressure Limits: Photohelic
®
-20" Hg. to 25 psig (-0.677 to
1.72 bar). MP option; 35 psig (2.41 bar), HP option; 80 psig
(5.52 bar). 36003S – 36010S; 150 psig (10.34 bar). 36020S and
higher; 1.2 x full scale pressure.
Temperature Limits: 20 to 120°F.
(-6.67 to 48.9°C) Low temperature option available.
Process Connections: Photohelic
®
, 1/8˝ female NPT.
Size: Photohelic
®
, 4˝ (101.6 mm) dial face, 5˝ (127 mm) O.D. x 8-
1/4˝ (209.55 mm).
Weight: Photohelic
®
, 4 lbs. (1.81 kg).
SWITCH SPECIFICATIONS
Switch Type: Each setpoint has 2 Form C relays (DPDT).
Repeatability: ±1% of full scale.
Electrical Rating: Photohelic
®
, 10A @ 28 VDC, 10A @ 120,
240 VAC.
Electrical Connections: Screw Terminals.
Power Requirements: 120 VAC, 50/60 Hz; 240 VAC & 24 VAC
Power optional.
Mounting Orientation: Diaphragm in vertical position. Consult
factory for other position orientations.
Set Point Adjustment: Adjustable knobs on face.
Agency Approvals: Photohelic
®
UL, CSA, CE.
