RHCM-40

Supported Applications

The Omega RHCM-40 Series is an optical chilled mirror dew point transmitter designed for continuous moisture content measurement in gases. The instrument utilizes the chilled mirror dew point condensation principle and a platinum resistance RTD for temperature measurement. Documented applications include process control and energy management, with optional capabilities for air temperature and relative humidity monitoring.

Operating Conditions & Performance

The RHCM-40 series provides specific performance metrics based on the chilled mirror sensor technology:

• Dew Point Range: -40 to 60°C (-40 to 140°F) (Standard)
• Air Temperature Range: -40 to 60°C (-40 to 140°F) (Optional)
• Relative Humidity Range: 1 to 95% RH (Optional)
• Accuracy: ±0.2°C for both dew point and temperature
• Repeatability: ±0.05°C
• Hysteresis: Negligible
• Response Time: 1°C/second not including settling time
• Pressure Rating: 100 psig maximum (higher pressure available on special order)

The instrument is powered by a standard 24 Vdc ±20% supply with a 1 A maximum, or an optional AC Universal Supply of 85 to 230 Vac.

Configuration Options

The series supports multiple mounting configurations and enclosure materials tailored for different installation environments:

• Housing Materials: IP65 plastic enclosure (for -PL models) or Aluminum enclosure (for -AL models)
• Mounting Options: Wall Mount, Duct Mount, Pipe Mount, and Remote Mount
• Process Connections: Includes 1¼ NPT brass pipe fitting for pipe mount configurations; duct mount flange kits are available for specific models.
• Cable Lengths (Remote): Standard remote cable is 3 m (10') with a maximum of 15.2 m (50'); Remote Mount -AL-R includes a 3 m (10') cable between sensor and electronics, while -PL-R models include a 1.8 m (6') cable.
• Outputs: Configurable for 4 to 20 mA (load resistance: 0 to 250 Ω), 0 to 5 Vdc or 0 to 10 Vdc (load resistance: 1 kΩ or higher), RS232 bi-directional serial output, and two programmable alarm relays.
• Relay Specifications: Contact rating is Normally open (NO) 3 A at 25 Vac, or 30 Vdc. Relays are assignable to Clean mirror/Alarm 1 (K1) or Servolock/Alarm 2 (K2).

Sensor and Mirror Options: The standard mirror is chrome plated; optional mirrors include gold or platinum coatings. Wetted materials correspond to the selected mirror finish.

Optional Features & Accessories

• Air Temperature Sensors: Available as Remote mount (-ATDT/R), Wall mount (-ATDT/W for -W models only), or Integrated 100Ω Pt RTD sensor embedded in the dew point sensor (-ATDT/I).
• Display: Two Line LCD (Graphical Display with 3 Parameters Displayed at One Time) available as option -RD for -PL models.
• Sample Chambers: Flow-Through Sample Chamber options include low pressure sample chamber (-SC), max pressure 100 psig flow through (-SC1), and High Pressure (20 bar).
• Power & Control: Universal power supply option (-ACDT) for 85 to 230 Vac, 50/60 Hz; Sample module universal operation (-SMU); Aspirator kit (-AR).
• Cabling Extensions: Additional cable length up to 15.2 m (50') via option -ECDT.

Key Product Differences

The RHCM-40 series is distinguished by enclosure material and mounting style, defined in the model number guide as RHCM-40 - <MOUNTING> - <ENCLOSURE> - <OPTIONAL FEATURES>.

• Enclosure Types: Models with suffixes starting with "PL" feature an IP65 plastic enclosure. Models with suffixes starting with "AL" utilize an aluminum enclosure.
• Mounting Configurations:

• -W: Wall mount (includes 2-staged chilled mirror sensor, analog outputs, RS232, alarm relays)
• -D: Duct mount (includes duct mount flange kit)
• -R: Remote mount (separates sensor and electronics with a cable; -PL-R includes 1.8 m (6') cable, -AL-R includes 3 m (10') cable)
• -P: Pipe mount (includes 1¼ NPT brass pipe fitting rated for 100 psi maximum)

Note regarding the LCD option (-RD): When ordered, all three parameters are displayed on the screen; however, only two of these parameters can be assigned to the two analog outputs.