The Dwyer RHPX-3SRA0-08 is a remote sensor humidity and temperature transmitter from the Dwyer Series RHPX, built around a capacitive polymer humidity sensor rated to ±3% RH across 10% to 90% RH at 25°C (77°F). Humidity output is field selectable between 4-20 mA, 0-5 V dc and 0-10 V dc, alongside an active analog temperature output on the same selectable range. The humidity sensing element is remote from the housing on a 2.4 m (8 ft) cable, letting the enclosure sit clear of the measured air stream. The housing is UL 94 V-0 rated to IP66 / NEMA Type 4X, and on-board DIP switches select imperial or metric units, voltage or current output, and whether the humidity channel reports relative humidity, dew point, enthalpy or absolute humidity.
- Remote humidity sensing, where the housing sits clear of the air being measured and the sensing element is on the supplied cable
- Air economizer sequences using the selectable enthalpy or dew point humidity output
- Dwyer publishes these Series RHPX applications: air economizers, outdoor humidity and temperature reference, pool room humidity monitoring, building energy management systems, commercial HVAC systems, clean rooms, museums and data centers
Key Features
Active Analog Temperature Output
Temperature is transmitted on a field-selectable 4-20 mA, 0-5 V dc or 0-10 V dc output from a solid state band gap element accurate to ±0.9°F @ 77°F (±0.5°C @ 25°C).
±3% RH Capacitive Polymer Sensor
Humidity sensor accuracy is ±3% at 10% to 90% RH and 25°C (77°F), across a full 0% to 100% measurement range, with 0.1% RH resolution.
Four Selectable Humidity Metrics
DIP switches 4 and 5 set the humidity channel to relative humidity, enthalpy, dew point or absolute humidity. Absolute humidity spans 0 to 50 g/m3, dew point -75°C to 60°C, and enthalpy -40 to 411 kJ/kg.
Field-Selectable Output and Units
DIP switch 1 selects metric or imperial units, switch 2 selects 0-10 V or 0-5 V, and switch 3 selects voltage or 4-20 mA output. Default is imperial units, 4-20 mA, %RH. On-board trimmers allow ±3.5% RH and ±5°F field offset.
Compliance
The Series RHPX carries BTL and CE compliance. Dwyer qualifies its UL 60335-2-40 listing as meeting UL 60335-2 clause 30.103DV.1 through UL 2043 compliance. UL 2043 plenum compliance is limited to the specific model groups named in DS-RHPX Rev.1, which do not include this model.
Serviceable Installation Details
Removable terminal block accepts up to 18 AWG wire, the lid stays attached, and a 1/2 in NPS electrical entry ships with a cable gland.
Technical Specifications
| Model / SKU | RHPX-3SRA0-08 |
| Sensor Configuration | R — Remote humidity sensor |
| Enclosure Size | S — Small enclosure |
| Humidity Measurement Range | 0% to 100% humidity |
| Humidity Sensor Accuracy | ±3%, at 10% to 90% RH and 25°C (77°F) |
| Humidity Sensor | Capacitive polymer |
| Temperature Measurement Range | -40°C to 60°C (-40°F to 140°F) |
| Humidity Analog Output | 4-20 mA or 0-5 V dc, 0-10 V dc at 5 mA max, field selectable |
| Active Temperature Analog Output | 4-20 mA or 0-5 V dc, 0-10 V dc at 5 mA max, field selectable |
| Active Temperature Accuracy (Solid State Band Gap) | ±0.9°F @ 77°F (±0.5°C @ 25°C) |
| Passive Temperature Sensor | None on this model (order code 0) |
| Power Requirements | 4-20 mA: 10 to 35 Vdc. Voltage output: 15 to 35 Vdc or 15 to 29 Vac |
| Wiring Connection | Removable terminal block, 18 AWG maximum |
| Resolution | Relative humidity 0.1%; temperature 0.1°F/°C; absolute humidity 0.1 g/m3 |
| Additional Calculations | Absolute humidity 0 to 50 g/m3 or 0 to 3000 lb/mmcf; dew point -75°C to 60°C (-102°F to 140°F); enthalpy -40 to 411 kJ/kg or -17 to 177 Btu/lb |
| Operating Temperature Range | -40°C to 60°C (-40°F to 140°F) |
| Storage Temperature | -40°C to 70°C (-40°F to 158°F) |
| Display | None on this model |
| Remote Sensor Cable Length | 2.4 m (8 ft) (order code 08) |
| Electrical Entry | 1/2 in NPS thread, cable gland included |
| Enclosure Material | UL 94 V-0 |
| Enclosure Rating | IP66, NEMA Type 4X |
| Compliance | BTL, CE. Dwyer qualifies UL 60335-2-40 as meeting UL 60335-2 clause 30.103DV.1 through UL 2043 compliance, which this model does not carry. |
| Warranty | 5 year limited warranty |
Documentation
Related Products
Frequently Asked Questions
Reading the Dwyer order code left to right: RHPX is the series, 3 is 3% RH accuracy, S is the small enclosure, R is Remote humidity sensor, A is the selectable analog output, 0 is no passive temperature sensor, and 08 is the cable length option.
No. The two-line alphanumeric display is a separate -LCD option on the Series RHPX order code.
Yes. DIP switches 4 and 5 set the humidity channel output to relative humidity, enthalpy, dew point or absolute humidity. The default setting is %RH.
It depends on the output mode selected. In 4-20 mA mode the transmitter needs 10 to 35 V dc. In voltage output mode it needs 15 to 35 V dc or 15 to 29 V ac. The 4-20 mA models are not designed for AC voltage operation.
No. The UL 2043 compliance footnote in DS-RHPX Rev.1 does not cover this model, so no plenum rating is claimed for it.
No. Dwyer states the Series RHPX requires no routine maintenance, is not field serviceable, and cannot be repaired. Field repair should not be attempted and may void the warranty.
5 Year Limited Warranty. The Dwyer Series RHPX carries a five year limited warranty as published on the Dwyer Series RHPX catalog page. Warranty and return handling follow the Terms and Conditions of Sale published by Dwyer Instruments, LLC. Contact customer service for a Return Materials Authorization (RMA) number before shipping any product back for repair, and include a brief description of the problem plus any application notes.
The Series RHPX requires no routine maintenance, is not field serviceable, and cannot be repaired. Field repair should not be attempted and may void the warranty.
ZOT Supply is an authorized DwyerOmega distributor. Warranty support is handled through ZOT Supply at sales@zotsupply.com or 855-825-2811.
- Sensor Type:
- Remote Probe
- Humidity Element:
- 3%
- Series:
- RHPX
- Humidity Output:
- 4–20 mA (loop output)
- Humidity Output:
- 0–5V or 0–10V (jumper-selectable)
- Supported Protocols:
- None (analog)
- Temperature Element:
- Solid State Band Gap
- Display:
- No Display
- Enclosure:
- NEMA 4X Enclosure
- CO2 Element:
- None
- Material:
- Plastic
