4-20 mA Pressure Transmitters for Oil, Gas and Process Lines: Gauge vs 2088 Display vs 3051DP Differential (Q&A)

Short answer: for a plain gauge-pressure reading on an oil, water, gas or air line, a threaded G1/2 transmitter with 4-20 mA, 0-10 V or RS485 output covers -1 bar to 600 bar at the lowest cost. If you want a local LED reading at the tap and a choice of G or NPT threads, look at the 2088-style housing. If you need differential pressure (orifice-plate flow, DP level on a pressurized vessel, filter DP) or HART configuration, choose a 3051DP-format smart DP transmitter. Find it by part number. Buy it with the specs in front of you.

Specs at a glance: 4-20 mA pressure transmitters

Product	Measures	Outputs (as listed)	Ranges offered	Connection / display	Price
G1/2 industrial pressure transmitter (QDW90A)	Gauge / vacuum pressure	4-20 mA, 0-10 V or RS485; 24 VDC	-1…0 bar up to 0-600 bar (15 ranges)	G1/2 thread; no display listed	$63.99 – $84.99
YB-2088 digital pressure transmitter	Gauge / vacuum pressure, diffused-silicon sensor	4-20 mA or RS485; 12-24 VDC	0-10 kPa up to 0-60 MPa, plus -0.1…0 and -0.1…1 MPa (17 ranges)	G1/4, G1/2, M20x1.5, NPT1/4 or NPT1/2; local LED display	$207.99 – $262.99
3051DP smart differential pressure transmitter	Differential pressure, capacitive silicon sensor	4-20 mA + HART, or RS485; 12-24 VDC	0-1 kPa up to 0-4 MPa, plus bidirectional ranges such as -10…10 kPa (20 ranges)	Coplanar DP body; LCD with local keys; 0.1% standard accuracy; -20 to 80 °C	$497.99 – $516.99

Which one fits my application?

Application	Look at	Why
Pump discharge, compressor, hydraulic or water line pressure into a PLC	G1/2 transmitter (QDW90A)	Widest range set (to 600 bar), choice of 4-20 mA, 0-10 V or RS485, lowest price
Wellhead, separator or tank pressure where the operator reads the value at the tap	YB-2088	Local LED display, NPT1/4 or NPT1/2 threads offered, 4-20 mA or RS485
Gas or liquid flow with an orifice plate or V-cone	3051DP	Differential measurement; HART lets you set range and damping from a HART modem
Differential level in a pressurized vessel; filter, strainer or heat-exchanger DP	3051DP	Measures the difference between two ports, which a gauge transmitter cannot do
Signal must go to a SCADA or Modbus master with no analog input card	RS485 version of any of the three	Read it directly on an RS485 Modbus bus

What goes with a pressure transmitter

• Read it on a panel: a digital panel meter for 4-20 mA / 0-10 V signals ($18.99 – $43.99) shows the value in engineering units.
• Switch a pump or alarm on pressure: the 4-20 mA process level / pressure controller ($86.99) has 4 relays, a 24 VDC loop supply for a 2-wire transmitter and RS485.
• Configure a HART transmitter: the WS232UP USB HART modem ($128.99) has a built-in 24 VDC loop supply and 270 Ω resistor, so a 3051DP can be set up on the bench from a laptop (configuration software not included).
• Put the 4-20 mA signal on Modbus: the 4AI-4DI-4DO Modbus RTU module ($33.99 – $34.99) reads 4 analog inputs onto RS485. Then choose the link (Ethernet, WiFi, cellular or LoRa) in our RS485 Modbus gateway guide.

Questions buyers ask

What is the difference between a pressure transmitter and a differential pressure transmitter?

A pressure transmitter has one process port and measures against atmosphere (gauge) or vacuum. A differential pressure (DP) transmitter has two ports, high and low, and outputs the difference between them. DP is used for orifice-plate flow, level in a pressurized vessel and filter or strainer loss.

Should I order 4-20 mA or RS485?

Order 4-20 mA if the signal goes to a PLC analog input, a panel meter or a relay controller: it is a 2-wire loop that tolerates long cable runs. Order RS485 if you read the transmitter directly from a Modbus master or gateway and want several devices on one cable. See 4-20 mA vs 0-10 V for analog signal choice.

How do I pick the range?

Pick a range whose top is above the highest pressure the line will see, but not far above it: the error is a percentage of the full range, so a 0-600 bar sensor on a 10 bar line reads poorly. State the range in the order; each listing above shows the ranges offered.

Are the YB-2088 and 3051DP rated for hazardous areas?

The suppliers describe both housings as explosion-proof, but no hazardous-area certificate (ATEX, IECEx, UL/CSA Class I Div 1) is included in either listing. Confirm suitability for your area classification before installing them in a hazardous location.

What is HART used for?

HART carries digital data on top of the 4-20 mA signal. With a HART modem or communicator you can read the transmitter’s value and settings and change range, units or damping without opening the housing. The 4-20 mA analog signal keeps working for the PLC.

What accuracy do they have?

The 3051DP listing states 0.1% standard accuracy. The G1/2 and YB-2088 listings do not state an accuracy figure, so do not assume one; if accuracy is a purchase requirement, the 3051DP is the only one of the three with a stated value.

Can I use a pressure transmitter for a safety shutdown?

No. None of these transmitters carries a safety (SIL) rating. Use them for measurement and monitoring, not as the sensor of a safety shutdown system.

See the pressure on your phone: AutomationBotX Cloud

Once the transmitter’s 4-20 mA or RS485 signal reaches a Modbus gateway, AutomationBotX Cloud shows live readings and alarms in the app on one dashboard. It is read-only monitoring: it never sends commands to your equipment, so it does not replace a control or safety system. First 10 machines free, no card needed. How the signal gets from the sensor to your phone.

Need several units?

Ask for a written volume quote on our wholesale page. More field equipment: oil and gas automation.

Free US shipping on every order. Specs above come from the product listings; if a value you need is not listed, it is not stated by the supplier. Prices checked on November 13, 2026 and may change; the product page shows the current price.