Pressure Measurement

Differential Pressure Transducer

Model 264 (HVAC Application)

model 264 pressure transducer hvac application


Setra Model 264 Pressure Transducer sense differential or gauge (static) pressure and convert this pressure difference to a proportional electrical output for either unidirectional or bidirectional pressure ranges. The 264 Series is offered with a high level analog 0 to 5 VDC or 4 to 20 mA output.

In a typical Setra configuration, Model 264 a compact housing contains two closely-spaced, parallel, electrically-isolated metallic surfaces, one of which is essentially a diaphragm capable of slight flexing under applied pressure. The diaphragm is constructed of low-hysteresis material such as 17-4 PH SS or a proprietary compound of fused glass and ceramic (Setracerama). These firmly secured surfaces (or plates) are mounted so that a slight mechanical flexing of the assembly, caused by a minute change in applied pressure, alters the gap between them (creating, in effect, a variable capacitor). The resulting change in capacitance is detected by a sensitive linear comparator circuit (employing proprietary, custom-designed ASICs), which amplifies and outputs a proportional, high-level signal.

  • Up to 10 PSI overpressure on all ranges
  • Installation time minimized with snap track mounting and easy – to – access pressure ports and eectrical connections
  • 0 to 5 VDC or 2-wire 4 to 20 mA analog outputs are compatible with energy management systems
  • Reverse wiring protection
  • Internal regulation permits use with unregulated DC uower uupplies
  • Fire retardent case (UL 94 V-0 Approved)
  • Meets CE conformance standards
  • Heating, Ventilating and Air Conditioning (HVAC)
  • Energy Management Systems
  • Variable Air Volume and Fan Control (VAV)
  • Environmental Pollution Control
  • Lab and Fume Hood Control
  • Oven Pressurization and Furnace Draft Controls

Technical Details

Accuracy* RSS (At Constant Temp.)±1.0% FS±0.4% FS ±0.25% FS
Non-Linearity, BFSL±0.96% FS±0.38% FS ±0.22% FS
Hysteresis0.10% FS0.10% FS 0.10% FS
Non-Repeatability0.05% FS0.05% FS 0.05% FS
Thermal Effects**
Compensated Range °F(°C) 0 to +150 (-18 to +65)
Zero/Span Shift %FS/°F(°C)±0.033 (±0.06)
Maximum Line Pressure10 PSI
OverpressureUp to 10 PSI in Positive or Negative Direction
Long Term Stability0.5% FS/1 YR
Position EffectRange Zero Offset (%FS/G)
(Unit is factory calibrated at 0g effect in the vertical position.)To 0.5 in. / To 1.0 in. / To 2.5 in. / To 5 in. 0.60 / 0.50 / 0.22 / 0.14
* RSS of Non-Linearity, Hysteresis, and Non-Repeatability.
**Units calibrated at nominal 70°F. Maximum thermal error computed from
this datum.

Environmental Data

Operating* °F (°C)0 to +175 (-18 to +79)
Storage °F (°C)-65 to +250 (-54 to +121)
*Operating temperature limits of the electronics only. Pressure media temperature may be considerably higher or lower.

Physical Description

CaseFire-Retardant Glass Filled
Polyester (UL 94 V-0 Approved)
MountingFour screw holes on removable
zinc plated steel base (designed
for 2.75” snap track)
Electrical ConnectionScrew Terminal Strip
Pressure Fittings3/16” O.D. barbed brass pressure fitting for 1/4” push-on tubing
Zero and Span AdjustmentsAccessible on top of case
Weight (Approx.)10 ounces

Pressure Media

Typically Air or Similar Non-Conducting Gases

Electrical Data (Voltage)

Circuit 3-Wire (Com, Exc, Out)
Excitation9 to 30 VDC
Output*0 to 5 VDC**
Bidirectional Output at Zero Pressure 2.5 VDC**
Output Impedance 100 ohms
*Calibrated into a 50K ohm load, operable into a 5000 ohm load or greater.
**Zero output factory set to within ±50mV (±25 mV for optional accuracies).
**Span (Full Scale) output factory set to within ±50mV. (±25 mV for optional accuracies).

Electrical Data (Current)

Output*4 to 20 mA**
Bidirectional Output at Zero12 mA**
External Load0 to 800 Ohms
Minimum supply voltage (VDC) = 9+ 0.02 x (Resistance of receiver plus line).
Maximum supply voltage (VDC) = 30+ 0.004 x (Resistance of receiver plus line).
*Calibrated at factory with a 24 VDC loop supply voltage and a 250 ohm load.
**Zero output factory set to within ±0.16mA (±0.08 mA for optional accuracies).
**Span (Full Scale) output factory set to wtihin ±0.16mA (±0.08 mA for
optional accuracies).

Note: Specification are Subject to change without notice