Pressure Measurement
Differential Pressure Transducer
Model 267/267MR (HVAC Application)
Setra’s Model 267 and 267MR Differential Pressure Transducer sense gauge (static) or differential pressure and convert this pressure difference to a proportional electrical output. The 267 series is offered with a high level voltage output or 4-20 mA current output. The 267MR offers multi-range capability and field configurable 0-5 VDC or 0-10 VDC output, as well as a 4-20 mA output.
In a typical Setra configuration, Model 267 and 267MR has 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 (Setraceramâ„¢). 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.
- Model 267MR Offers Multi-Range Capability, 6 Field Selectable Ranges via Dip Switches, and Field Selectable 0-5 or 0-10 VDC Output
- Model 267 Offers an Optional 3 1/2 Digit LCD Display with a 0.5% FS Standard Accuracy
- NEMA 4/IP65 Rated Housing
- Optional accuracy as high as 0.25% full scale
- 24 VAC or 24 VDC Excitation
- PG-9, PG13.5 or Conduit Electrical Termination
- Integral Static Pressure Probe
- Ranges as low as 0.1 in. W.C. (25 Pa)
- Meets CE Conformance Standards
- Heating, Ventilating and Air-Conditioning (HVAC)
- Energy Management Systems
- Static Duct Pressure
- Clean Room Pressure
- Oven Pressurization and Furnace Draft Controls
Technical Details
| Performance | ||
| Standard | Optional | |
| Accuracy* RSS (At Constant Temp.) | ±1.0% FS | ±0.4% FS ±0.25% FS |
| Non-Linearity, BFSL | ±0.98% FS | ±0.38% FS ±0.22% FS |
| Hysteresis | 0.10% FS | 0.10% FS 0.10% FS |
| Non-Repeatability | 0.05% FS | 0.05% FS 0.05% FS |
| Thermal Effects** | ||
| Compensated Range °F(°C) | +40 to +150 (+5 to +65) | |
| Zero/Span Shift %FS/°F(°C) | ±0.033 (±0.06) | |
| Maximum Line Pressure | 10 PSI | |
| Overpressure | 10 PSI in Positive or Negative Direction | |
| Warm-up Shift | ±0.1% FS Total | |
| Position Effect** | ||
| Range | To 0.5 in. / To 1.0 in. / To 2.5 in. / To 5.0 in. | |
| *RSS of Non-Linearity, Non-Repeatability and Hysteresis. **Units calibrated at nominal 70°F. Maximum thermal error computed from this datum. ***Unit is factory calibrated at 0g effect in the vertical position. | ||
Physical Description
| Case | Fire-Retardant Glass Filled Polyester (UL 94 V-0 Approved) | |
| Mouting | Four screw holes on removable zinc plated steel base (designed for 2.75” snap track) | |
| Electrical Connection | Screw Terminal Strip | |
| Electrical Termination | PG-9/PG13.5 Strain Relief, 1/2″ Conduit Opening, or 9 Pin D-Sub Connector* | |
| Zero and Span Adjustments | Accessible on top of case | |
| Display (Optional on 267 only) | 3 1/2 Digit LCD Integral | |
| Display | (1.74″W x 0.78″H) | |
| Pressure Fittings | 3/16″ O.D. Barbed Brass for 1/4″ Push-On Tubing (Standard) Static Pressure Probe (Optional) 1/4″ NPTF Brass (Optional) | |
| Mounting | 2 Mounting Tabs with 0.18″ Holes Pressure Probe Assembly is Supplied with a 7.8″ 6061 Aluminum Alloy Probe and a Gasket to Seal Against the Duct | |
| Weight (Approx.) | 9.0 ounces (255 grams) 9.5 ounces (Duct Probe Assembly) | |
| *9 pin D-sub Connector is not suitable for NEMA4/IP-65 environments. | ||
Electrical Data (Voltage)
| Circuit | 3-Wire (Exc, Gnd, Sig) Protected from Miswiring | |
| Excitation (for 0-5 VDC Output) | 9 to 30 VAC/12 to 40 VDC | |
| Excitation (for 0-10 VDC Output) | 11 to 30 VAC/13 to 40 VDC | |
| Model 267 | ||
| Output* | 0 to 5 VDC** 0 to 10 VDC** | |
| Model 267MR | ||
| Output* (Field Selectable) | 0 to 5 VDC** 0 to 10 VDC** | |
| Bidirectional Output at Zero | Mid-Range of Specified Output | |
| Output Impedance | 100 Ohms | |
| Re-Ranging (267MR only) | 5 Position Dip Switches (Located Inside Case) | |
| *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)
| Circuit | 2-Wire Protected from Miswiring | |
| Output* | 4 to 20 mA** | |
| Bidirectional Output at Zero | 12 mA | |
| External Load | 0 to 800 Ohms | |
| Minimum loop supply voltage (VDC) = 9 + 0.02 x (Resistance of receiver plus line). Maximum loop supply voltage (VDC) = 30 + 0.004 x (Resistance of receiver plus line). Re-Ranging (267MR only) 4 Position Dip Switches (located inside case) | ||
| *Calibrated 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) | ||
Pressure Media
| Typically Air or Similar Non-Conducting Gases |
Environmental Data
| Temperature | ||
| Operating* °F (°C) | 0 to +150 (-18 to +65) | |
| Storage °F (°C) | -65 to +180 (-54 to +82) | |
| *Operating temperature limits of the electronics only. Pressure media temperature may be considerably higher or lower. | ||
Note: Specification are Subject to change without notice
