The H4111 unit consists of a dual sensor, a full range (0 – 100% RH) Ultra-HII thin film capacitive humidity sensor and a thin film Platinum RTD sensor, Ultra 7, combined with a linearized 4-20 mA two-wire transmitter. The Platinum RTD provides repeatable, full range temperature compensation while the thin film capacitive RH sensor offers repeatable and accurate measurement.

The Ultra-HII and Ultra 7 are plug-in replaceable and mounted on the tip of a 3/8” diameter stainless steel probe and protected by a conductive reinforced polyester perforated shield. A porous stainless steel filter that can be advantageous for some applications, typically dirty or dust laden is optional. The interchangeable shield or filter screws off for easy sensor cleaning.

Rugged corrosion-resistant construction allows the sensor to withstand the normal impact of environmental and chemical substances. Common solvents, dirt, oil and other pollutants do not affect stability or accuracy. Sensor connections are encapsulated in a custom molded plug to exclude contamination.

The H4111 transmitter is a low noise, low drift, constant current device that accepts capacitive and resistive outputs from the sensor through circuit elements that provide sensor intrinsic safety. It produces a temperature corrected 4-20 mA current output which can be converted into an equivalent DC voltage output across an externally connected load resistor. The unit operates from 11.2 to 45.0 Vdc with virtually no change in calibration accuracy.

The unit is packaged in a NEMA 4X housing. Castings are low copper aluminum, fully anodized with an aliphatic urethane finish.

The unit can be mounted directly into the process ducting or can be adapted for pipe or wall mount applications.