EWS-WALL-MNT-ALL

Supported Applications

The Omega EWS Series Economical Wall-Mount Environmental Sensors and Transmitters are designed for office, computer room, or laboratory environments. These units provide temperature, humidity, and barometric pressure measurements compatible with process meters, controllers, recorders, data loggers, and data acquisition systems.

Operating Conditions & Performance

The series supports measurement in clean, dry air and non-corrosive gases within an acrylonitrile butadiene styrene enclosure. The units are intended for still or slow-moving air environments; they are not recommended for fast-moving-air applications.

• Temperature Transmitter (EWS-TX): Range of -18 to 57°C (0 to 135°F). Accuracy is ±0.7°C (±1.2°F) @ 25°C and ±1.4°C (±2.5°F) across full range in still air; accuracy shifts to ±1.4°C (±2.5°F) @ 25°C and ±1.7°C (±3°F) across full range in moving air.
• Temperature/Humidity Transmitter (EWS-RH): Temperature range of -15 to 60°C (5 to 140°F); Humidity range of 5 to 95% (non-condensing). Accuracy is ±1% RH; temperature accuracy matches the EWS-TX specifications for still and moving air.
• Barometric Pressure Transmitter (EWS-BP-A): Range of 20.8 to 32 inHg (10.2 to 15.7 psi) with operating temperature compensation across full range. Accuracy is ±1% of span @ 25°C (77°F) ±0.11%/°C (0.06%/°F).
• Sensor Elements: Thermocouple sensors offer accuracy of ±1.1°C (1.98°F); RTD sensor accuracy is ±1°C (1.8°F); and thermistor sensor accuracy is ±0.2°C (0.36°F). All sensor types have a maximum temperature rating of 60°C (140°F).

Response time for the transmitter models is 9 s in moving air (1m/s) and 30 s in still air for temperature; humidity response is 100 s from 20 to 90% and 60 s from 90 to 20%. Repeatability is ±0.3°C (±0.5°F).

Configuration Options

The EWS series offers multiple sensor technologies, output configurations, and mounting options.

• Sensor Types: Available as Thermocouple (Types J, K, T, E), RTD (100 Ω Pt 0.00385), or OMEGA® 400 Series thermistor (2252 Ω @ 25°C).
• Output Signals: Transmitter models provide user-selectable 4 to 20 mA or 1 to 5 Vdc outputs. The Temperature/Humidity model offers output scaled for 0 to 100% RH.
• Power Supply: Requires 12 to 24 Vdc @ 20 mA. Max loop resistance is calculated as Ω = (V supply – 8 V)/0.02 A.
• Mounting & Accessories: The standard unit requires a separate conduit box mounting bracket/wall plate adaptor kit (EWS-MB). Power supplies include PSR-24S, PSR-24L, and PSR-24L-230. Shielded 4-conductor transmitter cable TX4-100 is available.
• Lead Lengths: Standard sensor models come with 1 m (40") of lead wire. Longer lengths are configurable by adding a suffix such as "(#)FT" to the model number, subject to additional cost per foot over 3'.

Key Product Differences

The series is distinguished by sensor technology and measurement function:

• EWS-TC-(Type): Thermocouple sensors (Types J, K, T, E) with PFA coated 24 AWG lead material.
• EWS-RTD: RTD sensor using a 100 Ω Pt 0.00385 element with PFA insulated, 3-conductor 26 AWG stranded nickel-plated copper leads.
• EWS-TH: Thermistor sensor utilizing an OMEGA® 400 Series 2252 Ω @ 25°C element with PVC insulated, 2-conductor 22 AWG stranded nickel-plated copper leads.
• EWS-TX: Temperature transmitter providing analog output for wall mounting applications.
• EWS-RH: Combined temperature and humidity transmitter.
• EWS-BP-A: Barometric pressure transmitter with user-selectable 4 to 20 mA or 1 to 5 Vdc output.