Hu-1
Optical Chilled Mirror
Dew Point Transmitter
With Optional Humidity Measurement
RHCM-40 Series
RHCM-40-PL-P shown
smaller than actual size.
Inside view
U Wall, Duct and Pipe
Mount Models
U Remote Type Models
U 4-Wire RTD
Measurement
for Dew Point
U ±0.2°C Accuracy for
Both Dew Point and
Temperature
U Long-Term Stability
and Repeatability
U RS232, Bi-Directional,
Serial Output
U Electronics Housed
in IP65 Enclosure
(Wall Mount)
U Aluminum Housing for
Other Configurations
U 2 Analog Outputs
(4 to 20 mA/0 to 5 Vdc to
0 to 10 Vdc Selectable)
Optional Features
U Air Temperature
and Humidity
U 2 Line LCD (Graphical
Display with 3
Parameters Displayed
at One Time)
U AC Universal Supply
85 to 230 Vac
U Flow-Through
Sample Chamber
U High Pressure (20 bar)
The RHCM-40 Series dew
point transmitter is an optical
chilled mirror high performance
hygrometer designed to
continuously measure the
moisture content in gases. The
sensor provides accurate long
term repeatability and high
reliability performance for process
control and energy management.
The instrument is powered by
24 Vdc or optional AC universal
supply 85 to 230 Vac.
The RHCM-40 series uses
the chilled mirror dew point
temperature condensation
principle to determine the
water vapor concentration in
gas mixtures, and a platinum
resistance RTD to accurately
measure that temperature.
Options include air temperature
and humidity measurement.
There are two selectable
analog outputs which
include 4 to 20 mA,
0 to 5 Vdc, or 0 to 10 Vdc
and an RS232 serial port
as well as electrically
isolated relay contacts.
Specifications
Range:
Dew Point (Standard):
-40 to 60°C (-40 to 140°F)
Air Temperature (Optional):
-40 to 60°C (-40 to 140°F)
RH (Optional): 1 to 95%
Accuracy: ± 0.2°C for both dew point
and temperature
Hysteresis: Negligible
Repeatability: ±0.05°C
Response: 1°C/second not including
settling time
Flow Rate: Static to 3000 linear
feet/minute
Pressure: 100 psig maximum (higher
pressure available on special order)
Analog Outputs: 2 analog ouputs
(4 to 20 mA/0 to 5 Vdc to 0 to 10 Vdc
selectable)
Load:
4 to 20 mA: 0 to 250 Ω
0 to 5/10 Vdc: 1 kΩ or higher
Relay Outputs: 2 programmable
alarm relays
K1: Clean mirror/Alarm 1
K2: Servolock/Alarm 2
Contact Rating: Normally open
(NO) 3 A at 25 Vac, or 30 Vdc
Remote Cable Configuration:
Dew Point: 3 m (10') standard,
15.2 m (50') maximum
Air Temperature (Optional):
3 m (10') standard, 15.2 m (50')
maximum
For Dew Point: 2 stages of cooling
(TEC) with a depression of 60°C
Mirror:
Standard: Chrome plated
Optional: Gold or platinum
Power Supply: 24 Vdc ±20%,
1 A maximum
Weight: 1.4 kg (3 lb)
Electronics Module Outside
Dimensions: 130 H x 130 W x 76 mm D
(5.1 x 5.1 x 3")
Standard
H
u
Hu-2
To Order Visit omega.com/rhcm-40 for Pricing and Details
Model No. Description
RHCM-40-PL-W
Wall mount, dew point transmitter with an IP65 plastic enclosure, a 2-staged chilled mirror
sensor, 2 programmable analog outputs, RS232, alarm relays
RHCM-40-AL-W
Wall mount, dew point transmitter with an aluminum enclosure, a 2-staged chilled mirror
sensor, 2 programmable analog outputs, RS232, alarm relays
RHCM-40-PL-D
Duct mount, dew point transmitter with an IP65 plastic enclosure, a 2-staged chilled mirror
sensor, 2 programmable analog outputs, RS232, duct mount flange kit, alarm relays
RHCM-40-AL-D
Duct mount dew point transmitter with an aluminum enclosure, a 2-staged chilled mirror
sensor, 2 programmable analog outputs, RS232, alarm relays
RHCM-40-PL-R
Remote mount dew point transmitter with an IP65 plastic enclosure, a 2-staged chilled
mirror sensor, 2 programmable analog outputs, RS232, duct mount flange kit, 1.8 m (6')
cable between sensor and electronics, alarm relays
RHCM-40-AL-R
Remote mount dew point transmitter with an aluminum enclosure, 3 m (10') cable between
sensor and electronics
RHCM-40-PL-P
Pipe mount dew point transmitter with an IP65 enclosure, 1
1
⁄4 NPT brass pipe fitting
(100 psi maximum)
RHCM-40-AL-P
Pipe mount dew point transmitter with an aluminum enclosure, 1
1
⁄4 NPT brass pipe fitting
(100 psi maximum)
Comes complete with two stage chill mirror sensor (insertion probe style, 60°C depression), 24 Vdc input power, 2 selectable analog outputs,
RS232 (bi-directional), two programmable alarm relays, operator’s manual and NIST certificate.
Ordering Example: RHCM-40-PL-W-ATDT/W, wall mount, dew point transmitter with an IP65 plastic enclosure, a 2-staged chilled mirror
sensor, 2 programmable analog outputs, RS232, alarm relays and wall mount temperature probe with relative humidity.
Suffix Description
-D2
Two stage chill mirror flow through sensor
Suffix Description
-ATDT/R
Remote mount air temperature 100Ω Pt RTD probe [3 m (10' cable)]
-ATDT/W
Wall mount air temperature 100Ω Pt RTD probe (-W models only)
-ATDT/I
Integrated air temperature 100Ω Pt RTD sensor embedded in the dew point sensor
(-W, -D, -R models only)
Suffix Description
-ACDT
Universal power supply (85 to 230 Vac, 50/60 Hz)
-ECDT
Additional cable length [up to 15.2 m (50')] for both AT and/or dew point sensor
-RD
LCD (-PL models only)
-RTD
Resistive (100Ω Platinum RTD) dew point output
-AR
Aspirator kit
-SC
Cover, flow through, low pressure sample chamber with fittings
-SC1
Sample chamber flow through max pressure 100 psig
-SMU
Sample module universal 115/230 Vac operation
Accessory
Options
(Choosing one of the following three options will include relative humidity)
Note: When ordering the “-RD” LCD option, all 3 parameters will be displayed but only 2 of the parameters can be assigned to the two
analog outputs.
Two Analog Outputs Selectable for Dew Point, Temperature or Humidity