NOVUS RHT-WM and RHT-DM Transmitter User Guide
This document provides comprehensive instructions for the NOVUS RHT-WM and RHT-DM transmitters.
1. Safety Alerts
The following symbols are used on the equipment and throughout this manual to draw the user's attention to important information related to the safety and use of the equipment:
- CAUTION: Read the manual completely before installing and operating the device.
- CAUTION OR HAZARD: Risk of electric shock.
- ATTENTION: Material sensitive to static charge. Be sure to take proper precautions before handling it.
All safety recommendations in this manual must be followed to ensure personal safety and prevent damage to the instrument or system. If the instrument is used in a manner other than that specified, device safety protections may not be effective.
2. Introduction
The RHT-WM and RHT-DM transmitters feature highly accurate and stable sensors for measuring relative humidity and temperature. Measured values are converted into 4 to 20 mA output signals linearly related to their readings. These microprocessor-based devices can be configured via SigNow software or app. Humidity measurement and transmission can be configured between Relative Humidity and Dew Point.
3. Installation
3.1 RHT-DM: Mechanical Installation
The RHT-DM (Duct Mount) model has the following dimensions (in millimeters):
Figure 1 - Dimensions: The probe has a length of approximately 70.0 mm, a diameter of 60.0 mm, and a total height of 78.5 mm.
It is fixed with a flange. First, the flange is fixed to the duct wall. The probe is then inserted into the center hole of the flange and attached. Figure 2 shows the dimensions and drilling of the flange (in millimeters):
Figure 2 - Flange for attaching RHT-DM model: This diagram illustrates the flange dimensions and hole placement for mounting the RHT-DM probe.
The probe of this model comes in lengths of 150 mm or 250 mm and is available in metal or plastic.
3.1.1 RHT-DM Model: Plastic Probe
Figure 3 - RHT-DM with plastic probe: Diagrams show dimensions for the 150 mm and 250 mm plastic probe models.
3.1.2 RHT-DM Model: Metal Probe
Figure 4 - RHT-DM with metal probe: Diagrams show dimensions for the 150 mm and 250 mm metal probe models.
3.2 RHT-WM: Mechanical Installation
The RHT-WM (Wall Mount) model is designed for wall fixing. Removing its cover provides access to two fixing holes on the base and the wiring connector, as shown in Figure 5.
Figure 5 - Fixing holes and measurements for RHT-WM model (in millimeters): This diagram illustrates the RHT-WM wall mount dimensions, showing fixing points and connector location.
To ensure specified accuracy and protection, the transmitter should be fixed with the sensor capsule facing downwards.
3.3 Types of Tips
NOVUS offers 3 types of tips, available from authorized distributors:
- Polyamide tip: Features side openings for greater sensor exposure to the environment, resulting in a shorter response time. This tip is included with the RHT. Order code: 8803900120.
- High Density Polyethylene (PE) tip: Made of porous material, it protects the sensor from dust and solid particles. This reduces environmental contact, potentially leading to a longer response time compared to the Polyamide tip. Order code: 8803900110.
- Sintered Bronze Tip: Also made of porous material for sensor protection, it offers greater mechanical robustness than the Polyethylene tip. Similar to the PE tip, it may have a longer response time due to reduced environmental contact. Order code: 8803900100.
Note 1: Response time increase can depend on factors like air/gas speed where the sensor is inserted.
3.3.1 Installation
- Remove the tip from the RHT by slowly unscrewing it, ensuring only the tip rotates.
- The sensor circuit board will be exposed; do not touch it.
- Screw in the new tip carefully, without forcing the thread.
1 Dimensions in millimeters.
3.4 Electrical Installation
The figures below illustrate the necessary electrical connections:
Figure 6 - Connections: Shows a basic transmitter connection diagram.
Figure 7 - Connections on single source model: Depicts connections for a single source model.
Figure 8 - Connections on single source model (2 input channels): Illustrates connections for a single source model with two input channels.
Warning: The OUT1 loop must always be powered!
In the figures, LOAD represents the instrument measuring the output signal (e.g., indicator, controller, data logger). Electrical wires connect inside the transmitter via a cable gland.
3.4.1 Installation Recommendations
- Small electrical signal conductors should run separately from actuation conductors or high current/voltage conductors, preferably in grounded conduits.
- Power supply for electronic instruments should come from a proper instrumentation network.
- In control applications, consider potential system failures.
- RC FILTERS (noise suppressors) are recommended for contactor coils, solenoids, etc.
3.4.2 Precautions When Handling Sensors
Exposure to contaminant vapors or extreme humidity/temperature conditions can affect humidity sensor calibration. To reset calibration:
- Remove the sensor from the capsule.
- If solid particles are present, rinse with deionized water.
- Place the sensor in an oven at 80-90 °C with less than 5% RH for 24 hours.
- Alternatively, place the sensor in a location with 20-30 °C and greater than 75% RH for 48 hours.
- Replace the sensor in the capsule.
3.4.3 Sensor Replacement
If the humidity and temperature sensor is damaged, follow these steps for replacement:
- Step 1: Disconnect the equipment from the power supply. Locate the protective tip of the sensor. (This example shows sensor replacement on an RHT-DM transmitter, where the sensor is at the probe's end.)
- Step 2: Remove the tip by turning it counterclockwise.
- Step 3: With the tip removed, the sensor is exposed. Pull it forward to disconnect.
- Step 4: Connect the new sensor to the probe tip connector. Use clean anti-static gloves or other measures to prevent static discharge. Avoid unnecessary handling. Hold the sensor only by the connector area. Do not touch the sensor element itself. Clean anti-static gloves are recommended.
- Step 5: Replace the protective tip and turn it clockwise to secure it to the equipment.
4. Configuration
If the model is already configured with the proper ranges, no intervention is required for immediate installation. To change configuration, use SigNow software or app (refer to the SIGNOW SOFTWARE AND APP chapter).
To configure via software, connect the TxConfig-USB Configuration Interface (purchased separately) to the computer's USB port and run the software, as shown in Figure 9.
Figure 9 - TxConfig-USB Interface Connections: This diagram shows the TxConfig-USB interface connecting a transmitter to a computer's USB port.
To configure via the SigNow app, use an OTG cable with the TxConfig-USB Configuration Interface. Smartphones with On-The-Go (OTG) technology can connect directly to the device via USB. Figure 10 illustrates connecting the OTG cable to the equipment.
Figure 10 - OTG Cable: This diagram shows the connection of the TxConfig-USB interface to a smartphone using an OTG cable.
Warning: Incorrect cable positioning may prevent the device from being recognized by the application.
The SigNow configuration software can be downloaded for free from the NOVUS website (see SIGNOW SOFTWARE section). The SigNow app is available for free on the Google Play Store (see SIGNOW APP section).
5. SigNow Software and App
SigNow software and app are the primary tools for configuring and analyzing RHT data, enabling full equipment feature exploration via the TxConfig-USB Configuration Interface. This manual covers RHT features; for detailed SigNow operation, consult the specific operations manual available for download on www.novusautomation.com. Installation involves running SigNowSetup.exe.
5.1 SigNow Software
Upon running SigNow, the home screen is displayed (Figure 11).
Figure 11 - Home screen: Shows the SigNow software interface with options for Configuration, Diagnostic, Create Configuration, and Open Configuration.
For software communication, connect the RHT to the computer via a TxConfig-USB Configuration Interface and ensure USB drivers are installed (see CONFIGURATION chapter). Then, click on Configuration or Diagnostic.
5.1.1 Configuration Section
Clicking the Configuration button on the SigNow home screen reads the device's current configuration. This section displays all configurable features, divided into four sections: Temperature, Humidity, Output 1, and Output 2. The bottom of the screen shows equipment information like name, serial number, and firmware version.
5.1.1.1 Temperature Configuration
When connected, the following screen is displayed (Figure 12):
Figure 12 - Temperature configuration: This SigNow screen allows setting temperature parameters: Model, Output Type, Temperature Unit, Lower/Upper Limits, Zero Correction, and Filter.
Parameters available:
- Model: Displays the RHT model.
- Output type: Shows the equipment's output type.
- Temperature Unit: Allows setting the temperature unit (°C or °F).
- Lower Limit: Sets the minimum temperature for the output type.
- Upper Limit: Sets the maximum temperature for the output type.
- Zero Correction: Adjusts the reading offset.
- Filter: Sets a filter value for the measured quantity.
5.1.1.2 Humidity Configuration
The Humidity screen (Figure 13) allows setting humidity parameters:
Figure 13 - Humidity configuration: This SigNow screen allows setting humidity parameters: Model, Output Type, Lower/Upper Limits, Zero Correction, and Filter.
Parameters available:
- Model: Displays the RHT model.
- Output type: Shows the equipment's output type.
- Lower limit: Sets the minimum relative humidity percentage.
- Upper limit: Sets the maximum relative humidity percentage.
- Zero Correction: Adjusts the reading offset.
- Filter: Sets a filter value for the measured quantity.
5.1.1.3 Output 1 Configuration
The Output 1 screen (Figure 14) allows configuring output parameters:
Figure 14 - Output 1 Configuration: This SigNow screen allows configuring Output 1 parameters: Model, Physical Property, Reverse Output Polarity, Lower/Upper Limits, and Analog Output Error Action.
Parameters available:
- Model: Displays the RHT model.
- Physical property: Selects the measured property (Temperature, Humidity, or Dew Point). Can be disabled by selecting 'Off'.
- Reverse output polarity: Reverses the output polarity.
- Lower limit: Sets the minimum temperature for the output type.
- Upper limit: Sets the maximum temperature for the output type.
- Analog output error action: Defines the action taken for analog output errors (maximum or minimum error).
5.1.1.4 Output 2 Configuration
The Output 2 screen (Figure 15) allows configuring output parameters:
Figure 15 - Output 2 configuration: This SigNow screen allows configuring Output 2 parameters: Model, Physical Property, Reverse Output Polarity, Lower/Upper Limits, and Analog Output Error Action.
Parameters available:
- Model: Displays the RHT model.
- Physical property: Selects the measured property (Temperature, Humidity, or Dew Point). Can be disabled by selecting 'Off'.
- Reverse output polarity: Reverses the output polarity.
- Lower limit: Sets the minimum relative humidity percentage for the configured output type.
- Upper limit: Sets the maximum relative humidity percentage for the configured output type.
- Analog output error action: Defines the action taken for analog output errors (maximum or minimum error).
5.1.2 Diagnostic Section
The Diagnostic button on the SigNow home screen provides operational information and allows forcing output values. It can display current output, force values within the 4-20 mA range, or set maximum (21.5 mA) or minimum (3.6 mA) error values. This feature requires an external source and a TxConfig-USB Configuration Interface connected to the computer's USB port.
Figure 16 - Electrical connections of the example: Diagrams show electrical connections for using the diagnostic section with a TxConfig-USB interface, transmitter, and external connections.
After making the necessary connections, access the Diagnostic section. The 'Forcing' tab allows forcing values for outputs 1 and 2. Figures 17, 18, and 19 show examples of forcing values, including measurements using a multimeter, and forcing minimum/maximum error values. The graph displays temperature, relative humidity, and Dew Point values.
Figure 17 - Forcing values to output 1: Shows the SigNow diagnostic screen with a forced output value of 017.499 4 mADC, alongside measured values.
Figure 18 - Forcing minimum error values: Illustrates the SigNow diagnostic screen with a forced minimum error value of 3.60 mA for output 1.
Figure 19 - Forcing maximum error values: Illustrates the SigNow diagnostic screen with a forced maximum error value of 21.50 mA for output 1.
5.2 SigNow App
To use the SigNow app with your smartphone, connect the equipment using an OTG cable (not supplied) and the TxConfig-USB Configuration Interface. Enable TxConfig-USB use; the interface acts as an intermediary.
Figure 20 - Using TxConfig-USB: Shows a smartphone prompt asking to open SigNow for TxConfig-USB handling.
After connection, the app recognizes the equipment and displays the main screen (Figure 21).
Figure 21 - Main screen: Displays the SigNow app's main interface.
Clicking the Configuration button leads to the RHT Configuration section's main screen (Figure 22).
Figure 22 - Information screen: Shows the SigNow app's information screen, displaying equipment details like product name, serial number, and firmware version. The 'Config' button accesses configuration sections.
The Config section allows parameter configuration. The Diagnostic button on the home screen enables diagnostics and output forcing (see DIAGNOSTIC SECTION). SigNow app and software share similar screens and parameters for user-friendly integration. The SigNow manual, available on the NOVUS website, provides more details on features like firmware updates and configuration management.
6. Specifications
The following table details the technical specifications for the RHT-DM/RHT-WM transmitters:
| FEATURES | RHT-DM / RHT-WM |
|---|---|
| Humidity measurement | Total accuracy: See Figure 23. Measurement range: Configurable between 0 and 100 % RH or -100 and 103 °C (-148 and 217.4 °F) at Dew Point. Response Time (1/e (63 %)): 8 seconds @ 25 °C (with air moving at 1 m/s). |
| Sensor measurement temperature | Total accuracy: See Figure 23. Response Time (1/e (63 %)): Up to 30 s (with air moving at 1 m/s). DM Model: Configurable between -40 and 120 °C (-40 and 248 °F). WM Model: Configurable between -20 and 70 °C (-4 and 158 °F). |
| Transmitter temperature operating | Operating temperature: -20 to 70 °C (-4 to 158 °F), 0 to 95 % RH. Storage temperature: -20 to 80 °C (-4 to 176 °F). |
| Power Supply | 12 Vdc to 30 Vdc |
| Range of sensor readings | < 1.5 seconds |
| Outputs | 4-20 mA or 20-4 mA current, 2-wire type - loop powered. |
| Load on the outputs (RL) | RL (max. in Ohms) = (Vdc - 12) / 0.02, where: Vdc = Supply Voltage in Volts. |
| OUT1 and OUT2 outputs resolution | 0.0008 mA (4-20 mA) |
| Isolation between outputs | Isolated 4-20 mA outputs. |
| Protection Index | Electronic module housing: IP65. Sensor housing: IP40. |
| Cables | PG7 cable gland. |
| Operational Limits | Sensor and Probe (RHT-DM): See Figure 23. |
| Certifications | CE |
| Internal protection against reversal polarity of voltage supply. | Yes |
Table 1 - Technical specifications
IMPORTANT: The sensor may be damaged or lose calibration if exposed to atmospheres contaminated with chemical agents like Hydrochloric Acid, Nitric Acid, Sulfuric Acid, and Ammonia. Acetone, Ethanol, and Propylene Glycol can cause reversible measurement errors.
6.1 Accuracy of Measurements and Operating Limits of Sensors
Figure 23 - Accuracy in measuring humidity and temperature: This figure displays graphs illustrating the accuracy of relative humidity, temperature, and dew point measurements at 25 °C, as well as RH sensor operating conditions (Normal vs. Extreme).
6.2 Certifications
CE Mark: This is a Class A product. In a domestic environment, it may cause radio interference, requiring the user to take adequate measures.
7. Warranty
Warranty conditions are available on the NOVUS Automation website: www.novusautomation.com/warranty.
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