The EPT-301 combines a piezoresistive silicon sensor, a 316L stainless steel isolation diaphragm and digital signal conditioning. It is used for pressure monitoring in water treatment, hydraulic and pneumatic equipment, petrochemical systems, industrial automation and energy equipment.
The vented construction provides an atmospheric reference for the configured gauge-pressure instrument. Signal amplification, linear correction, interference suppression and surge protection condition the measurement for the selected output. Short-circuit and reverse-polarity protection are incorporated. Digital indication is available as a configuration choice.
| Parameter | Specification |
|---|---|
| Selectable measuring range | -100kPa to 100MPa; gauge or absolute configurations |
| Accuracy choices | Class 0.25, ±0.25%FS; class 0.5, ±0.5%FS |
| Overload pressure | 2× full scale or 110MPa, whichever is smaller |
| Plug-in version temperature | -30°C to 80°C |
| Cable version temperature | -10°C to 70°C |
| Outputs | Two-wire 4–20mA; three-wire 0–5V; three-wire 0–10V; four-wire RS485 |
| Supply | 10–28VDC; selected models support 5V ±0.1V |
| Isolation diaphragm | 316L stainless steel |
| Media compatibility | Fluids that do not corrode stainless steel or fluororubber (FKM), including compatible water, gas, oil and hydraulic media |
| Process connection | M20×1.5 as standard; other threads can be customized |
| Electrical connection choices | Hirschmann connector, aviation-style plug or cable leads |
| Version | Construction | Protection | Reference dimensions |
|---|---|---|---|
| B1 threaded | Four-pin plug with M20×1.5 process thread | IP65 | Length 130mm; body Ø31.5mm; SW30; thread length 22mm; main body 56.9mm; shoulder 10mm; connector height 51.3mm |
| B1 P1 | Four-pin plug, flush diaphragm and clamp ferrule | Length 108mm; body Ø31.5mm; ferrule Ø50.5mm with Ø43mm inner reference; neck 12mm; main body 56.9mm; connector height 51.3mm | |
| B2 cable | Sealed cable outlet | IP68 | Reference length 110mm; body Ø27mm; SW27; M20×1.5 thread, length 22mm |
| B3 cable | Cable gland outlet | IP65 | Reference length 105mm; body Ø27mm; SW27; M20×1.5 thread, length 22mm |
| B4 | M12×1 four-pin plug | Reference length 95mm; body Ø27mm; SW27; connector projection 9mm; M20×1.5 process thread, length 22mm | |
| B2 flameproof construction | Separate flameproof cable-outlet version | IP66 | Reference length 110mm; body Ø27mm; SW27; cable-entry thread G1/2 or M20×1.5; entry hex SW24; additional dimensions in the manual |
The photographed vented body has a 117mm overall reference height, 51mm connector width, 49mm main body section, 12mm hex section and 18mm thread. The standard body shown alongside has a 108mm reference height, 48mm connector width, 39mm main body section, 12mm hex section and 18mm thread. Select the dimensions for the actual body and connector configuration.
| Hirschmann output | Pin 1 | Pin 2 | Pin 3 | Earth-symbol contact |
|---|---|---|---|---|
| Two-wire 4–20mA | Supply + | Loop return | Unused | Not used in the signal circuit |
| Three-wire voltage | Supply - / common | Voltage output | ||
| Four-wire RS485 | RS485 A | RS485 B | GND |
| B2 cable colour | B4 M12 pin | Two-wire | Three-wire | Four-wire RS485 |
|---|---|---|---|---|
| Red | 1 | V+ | ||
| Blue | 2 | 0V / OUT+ | A | |
| Yellow | 3 | Unused | GND | |
| Green | 4 | Unused | B | |
Blue is the loop return in a two-wire circuit and the voltage signal in a three-wire circuit. The cable and M12 mappings differ from the Hirschmann pin assignments. Confirm the supplied connector and output configuration before wiring.
Choose a measurement point with stable temperature, little vibration and no strong electromagnetic interference. Route signal wiring separately from power cables. Use a short, clean impulse line where required, prevent sediment buildup and isolate the sensing element from corrosive or overheated media. For steam service, a water-filled impulse line provides separation from direct steam contact.
Check process sealing, polarity and terminal tightness before applying power. Allow approximately 30 minutes for stable operation. Do not touch the isolation diaphragm or exceed the configured pressure and temperature limits. The English manual contains all connector assignments, dimensional drawings and installation precautions.
