4-20mA Pressure Transmitter — 0–400 Bar, OEM China Factory
SEGMENsensor 4-20mA pressure transmitters convert process pressure to industry-standard 4-20mA loop current, compatible with all PLCs, DCS, and SCADA systems. Piezoresistive or ceramic sensing element, 316L stainless steel wetted parts, ±0.1% FS accuracy. Range 0–0.1 bar to 0–400 bar. Process connections G1/4", G1/2", 1/4" NPT, 1/2" NPT. CE and RoHS certified. OEM from Shenzhen since 2019, MOQ 10 pcs.
CE Certified±0.1% FS Accuracy0–400 Bar RangeMOQ 10 pcs
What is a 4-20mA Pressure Transmitter?
A 4-20mA pressure transmitter is a two-wire loop-powered device that converts pressure measurements into a proportional 4-20mA DC current signal. At minimum pressure (zero), output is 4mA; at maximum pressure (full scale), output is 20mA. The 4-20mA signal is the universal analog standard in industrial automation — immune to cable resistance losses, noise from motors and inverters, and compatible with any analog input card. Used in hydraulic systems, process piping, compressed air networks, water treatment, and chemical processing worldwide.
Specifications
4-20mA Pressure Transmitter — Full Technical Specifications
Standard specifications for SEGMENsensor 4-20mA pressure transmitters. Custom ranges, connections, and output variants available on request.
Parameter
Value
Measurement Principle
Piezoresistive / Ceramic capacitive
Output Signal
4-20mA (2-wire loop-powered)
Measurement Range
0–0.1 bar to 0–400 bar (specify at order)
Accuracy / Linearity
±0.1% FS (standard) / ±0.05% FS (precision)
Supply Voltage
12–36V DC (loop powered)
Loop Resistance
Max 600Ω at 24V supply
Wetted Materials
316L Stainless Steel diaphragm + housing
Process Connection
G1/4" male (standard); G1/2", 1/4" NPT, 1/2" NPT available
Electrical Connection
M12×1 4-pin connector (standard) / Hirschmann / flying lead
IP Rating
IP67 (standard) / IP68 (optional)
Burst Pressure
3× full scale (standard ranges)
Long-term Stability
±0.1% FS / year
Operating Temperature
-20°C to +85°C (media); -40°C to +85°C (ambient)
Compensated Temperature Range
0°C to +60°C
Vibration
10g, 10–2000 Hz
MOQ
10 pcs
Lead Time
2–3 weeks (standard) / 3–5 weeks (custom OEM)
Certifications
CE, RoHS
Selection Guide
Which 4-20mA Pressure Transmitter Variant Do You Need?
Match your pressure range and process medium to the right transmitter variant. Three tiers cover the full industrial pressure range from 0.1 to 400 bar.
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Standard Range 0.1–40 bar
Pneumatic systems, water treatment, HVAC, compressed air
Ceramic diaphragm — resistant to scale and mild media
PVDF or Hastelloy C diaphragm for chemical resistance
Hygienic tri-clamp process connection, flush diaphragm design
Custom wetted material — specify process medium at order
→ PT-S series (special media / flush)
Not sure which variant fits your pressure range or process medium?
Tell us your operating pressure, process medium, process connection type, and PLC brand — our engineers will recommend the correct model and range within 24 hours.
4-20mA Pressure Transmitter OEM — 8 Industry Applications
SEGMENsensor 4-20mA pressure transmitters are deployed across hydraulic systems, process plants, HVAC, semiconductor fabs, and more — wherever pressure must be measured with a long-run analog signal.
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Hydraulic Power Units
Monitor system pressure in HPU lines, filter differential pressure, accumulator pre-charge. Specify 0–250 or 0–400 bar range with high-pressure G1/2" connection.
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Compressed Air Systems
Line pressure monitoring, compressor outlet, air receiver tank. Standard 0–10 or 0–16 bar ceramic sensing transmitter, G1/4" connection, IP67.
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Water Treatment Plants
Pump discharge pressure, filter pressure drop, UV reactor inlet pressure. 316L SS wetted parts for potable water compliance. 0–10 to 0–40 bar range.
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Chemical Processing
Reactor vessel pressure, pipeline pressure monitoring. Specify process medium when ordering — Hastelloy C or PVDF diaphragm available for corrosive media.
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CNC Machine Tools
Coolant pressure, spindle air purge pressure, hydraulic clamp pressure. Compact G1/4" transmitter, M12 connector for easy PLC integration. IP67 standard.
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HVAC Systems
Chiller condenser and evaporator pressure, fan differential pressure, duct static pressure. Low-range 0–1 to 0–6 bar ceramic transmitters for building automation.
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Oil & Gas
Well head pressure, separator pressure, flow line pressure. Confirm ATEX-rated variant for hazardous area classification. 0–160 to 0–400 bar range available.
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Semiconductor Fabs
Ultra-pure water (UPW) pressure, process gas pressure, vacuum (specify negative range). Electropolished 316L SS wetted parts; low-outgassing cable option available.
Wiring & Connection
How to Wire a 4-20mA Pressure Transmitter
Three practical wiring scenarios — from basic 2-wire loop connection to PLC calibration formula.
01
Standard 2-Wire Connection
Brown (+) → PLC analog input (+) or +24V supply; Blue (–) → PLC analog input (–). The loop requires a PLC built-in 24V DC supply or an external 24V DC power source. Maximum loop resistance: 600Ω at 24V. No separate signal cable needed — power and signal share the same 2-wire loop.
02
Reading Current as Voltage
Insert a precision 250Ω shunt resistor in series with the loop. Measure voltage across the resistor: 4mA × 250Ω = 1V (zero pressure), 20mA × 250Ω = 5V (full scale). Any voltage-input analog card or digital multimeter can then read the signal — no current-input card required. Use a 0.1% precision resistor for best accuracy.
03
PLC Scaling Formula
Pressure = (mA – 4) ÷ 16 × Full-Scale Pressure. Example: full scale 10 bar, live reading 12mA → (12 – 4) ÷ 16 × 10 = 5 bar. In most PLCs, the analog input card outputs a raw integer (e.g., 0–27648 for standard 16-bit cards). Map: Pressure = (Raw – 5530) ÷ 22118 × Full-Scale Pressure (for 4mA = 5530 counts, 20mA = 27648 counts).
FAQ
Frequently Asked Questions
Technical and sourcing questions from OEM buyers about 4-20mA pressure transmitters.
What does 4-20mA mean in a pressure transmitter?
4-20mA is the output current range of the transmitter. 4mA represents the minimum (zero) pressure, and 20mA represents the full-scale (maximum) pressure. The 4mA live-zero allows the system to detect a wiring fault: if the signal drops below 4mA (e.g., to 0mA), it indicates a broken wire or power loss — not a valid low-pressure reading. The current loop is powered by the 24V DC supply in the PLC/DCS control panel (loop-powered, 2-wire). The current value is the same regardless of the cable length or resistance (up to the rated load resistance limit).
What pressure range should I select for my application?
Select a range where normal operating pressure falls between 60–80% of full scale. Example: a hydraulic system operating at 150–180 bar should use a 0–250 bar transmitter. Avoid over-ranging: operating near 100% full scale permanently reduces diaphragm life. Avoid under-ranging: operating below 20% of full scale wastes resolution. SEGMENsensor stocks: 0–1, 0–2.5, 0–4, 0–6, 0–10, 0–16, 0–25, 0–40, 0–60, 0–100, 0–160, 0–250, 0–400 bar. Vacuum ranges (negative) and compound ranges (e.g., -1 to +9 bar) available on request.
What is the difference between a pressure transmitter and a pressure transducer?
Both convert pressure to an electrical signal, but the output differs. A pressure transducer typically outputs a millivolt (mV) or voltage (0–5V, 0–10V) signal — requires amplification and is sensitive to cable length and noise. A pressure transmitter outputs 4-20mA — current-mode signal, immune to cable resistance (up to 600Ω load), resistant to electrical interference from motors and variable-frequency drives. For industrial process control with cable runs over 5 meters, always use a 4-20mA transmitter. For short-range lab or bench applications, a transducer may suffice.
Can I use a 4-20mA pressure transmitter on aggressive media (acids, alkalis)?
Standard 316L stainless steel is suitable for water, oil, mildly alkaline or acidic media (pH 4–10), hydraulic fluids, and fuels. For strong acids (H₂SO₄, HCl, HNO₃) or strong alkalis (NaOH >30%), specify the Hastelloy C diaphragm or PVDF-coated flush diaphragm variant. For food and pharmaceutical media, specify the hygienic variant with 316L flush diaphragm and tri-clamp or DIN 11851 dairy connection, compliant with surface roughness Ra ≤0.8 µm. Always specify your process medium when requesting a quote — incorrect material selection causes premature diaphragm failure.
What is flush diaphragm and when is it needed?
A flush (flat-face) diaphragm pressure transmitter has the sensing membrane flush with the process connection face — no internal cavity or impulse line where media can accumulate. Standard pressure transmitters have a small internal cavity and impulse port (typically G1/4"), where viscous media, slurries, or crystallizing fluids can plug the pressure path. Flush diaphragm transmitters are essential for: viscous fluids (resins, pastes, molasses), slurries (sewage, paper pulp), polymerizing media (epoxy), and food products requiring full CIP washdown. SEGMENsensor supplies flush diaphragm variants in G1/2" and 1" process connections.
What is the maximum loop resistance for a 4-20mA pressure transmitter?
At 24V DC supply, maximum loop resistance is (24V – 12V min supply) / 0.020A = 600Ω. This includes the cable resistance, PLC input impedance (typically 50–250Ω), and any series shunt resistors. At 28V DC supply, maximum loop resistance increases to (28V – 12V) / 0.020A = 800Ω. For long cable runs (>200 m with 0.5mm² cable ≈ 140Ω/km), calculate total loop resistance and ensure compliance. SEGMENsensor recommends 24–30V DC supply for standard installations. Minimum supply voltage at the transmitter terminals: 12V DC.
How do I calibrate a 4-20mA pressure transmitter?
SEGMENsensor pressure transmitters are factory-calibrated and shipped with a calibration report at 5 points (0%, 25%, 50%, 75%, 100% FS). Field zero and span adjustment is possible via the two-button configuration panel (where fitted) or via HART communicator for HART-enabled models. For most installations, no field calibration is required on receipt. Periodic calibration interval: typically 12–24 months per ISO 9001 instrumentation maintenance procedures. For quality-audited facilities, SEGMENsensor provides traceable calibration certificates (NIST/NIM traceable) on request.
What is the MOQ and lead time for OEM 4-20mA pressure transmitters from China?
MOQ 10 pcs for standard catalog configurations. Samples 1–2 pcs accepted. Standard configurations (range, connection, connector, IP67): 2–3 weeks. Custom configurations (non-standard range, flush diaphragm, special connection, HART output, IP68, OEM label): add 2–3 weeks. Private label (custom housing color, logo, tag plate): MOQ 50 pcs, 5–7 weeks. CE declaration of conformity, RoHS declaration, and calibration certificate with every order. Factory: Segmen Industrial Development Co., Ltd., Registration No. 91440300MAEUXXQU04, Shenzhen, Guangdong, China.
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Tell us your pressure range, process medium, process connection, and output — we'll send a quote and datasheet within 24 hours.
