Instruction Manual for Universal Temperature Humidity Transmitter

1. Introduction

The Ace Instruments ROTRONIC HYGROFLEX HF420 is a universal temperature and humidity transmitter designed for duct mounting. This robust device features well-proven sensors and digital signal processing, ensuring consistent performance and simplifying field maintenance through potentiometer-free digital calibration. It is an ideal solution for precise humidity and temperature measurements in various environments, including HVAC systems, greenhouses, museums, warehouses, railway stations, and office buildings for climate control.

This manual provides essential information for the proper installation, operation, and maintenance of your HF420 transmitter.

2. Safety Information

Please read all safety instructions carefully before installing or operating the device. Failure to follow these instructions may result in injury or damage to the device.

• Ensure the power supply is disconnected before any installation or maintenance work.
• Only qualified personnel should perform installation and wiring.
• Do not expose the device to extreme temperatures, humidity, or corrosive environments beyond its specified operating limits.
• Protect the device from mechanical shock and vibration.
• Use only specified power supply voltages (20-28 VDC).
• Do not attempt to open or repair the device yourself. Refer to authorized service personnel.

3. Product Overview

The ROTRONIC HYGROFLEX HF420 is a compact and robust transmitter. Key features include:

• Wide temperature and humidity measurement ranges.
• High accuracy with Pt100 1/3 Class B temperature sensor.
• Multiple analog output signals (0-1 V, 0-5 V, 0-10 V, 0(4)-20 mA).
• Optional digital communication interfaces: RS-485, USB, LAN, WLAN, MODBUS (ASCII).
• Internal data logging with 2000 data point memory.
• IP65 protection class for robust environmental resistance.
• Polyethylene dust filter for sensor protection.

Figure 3.1: Front view of the HF420 transmitter, showing the Rotronic Hygroflex branding and the cable gland connection point.

Figure 3.2: Side view of the HF420 transmitter, illustrating the integrated probe extending horizontally from the unit.

Figure 3.3: Top view of the HF420 transmitter, showing the probe positioned vertically, suitable for duct mounting applications.

4. Setup and Installation

The HF420 transmitter is designed for duct mounting. Follow these steps for proper installation:

1. Mounting Location: Select a suitable location in the ductwork that provides representative air flow and is free from obstructions.
2. Drilling: Drill the necessary holes for mounting the transmitter and for the probe insertion into the duct. Refer to the mounting template (if provided separately) for precise hole dimensions.
3. Mounting the Unit: Secure the transmitter housing to the duct using appropriate screws and anchors. The unit comes with a mounting kit including screws and wall plugs.
4. Probe Insertion: Carefully insert the sensor probe into the drilled opening in the duct. Ensure the probe is fully inserted and sealed to prevent air leakage.
5. Wiring: Connect the power supply (20-28 VDC) and analog/digital output signals to the screw terminals inside the unit. Use the M16 cable gland for secure cable entry. Ensure correct polarity for power connections.
6. Sealing: Ensure all connections and mounting points are properly sealed to maintain the IP65 rating and prevent air bypass.

Figure 4.1: The HF420 transmitter shown with its included mounting accessories, such as screws, wall anchors, and sealing washers.

Figure 4.2: An overhead view of the HF420 transmitter, displaying the probe, cable gland, and the circular mounting plate and gasket.

5. Operating Instructions

Once installed and powered, the HF420 transmitter will begin measuring temperature and humidity. The measured values are output via the configured analog or digital interfaces.

• Analog Outputs: The device provides 2 x 0-1 V, 0-5 V, 0-10 V, or 0(4)-20 mA signals. These outputs can be connected to a PLC, data logger, or control system.
• Digital Communication: For advanced monitoring and configuration, connect via RS-485, USB, LAN, or WLAN (optional interfaces). The device supports MODBUS (ASCII) protocol.
• Data Logging: The internal memory can store up to 2000 data points. Data can be retrieved and analyzed using the HW4 software via a ROTRONIC interface cable.
• Device Protection: Access to device settings can be protected by a password.
• Dew Point/Frost Point: The device can calculate and output dew point and frost point values.

For detailed configuration of output ranges, alarm functions, and communication settings, refer to the comprehensive software manual for HW4.

6. Maintenance

Regular maintenance ensures the long-term accuracy and reliability of your HF420 transmitter.

• Calibration: The recommended calibration interval is specified in the service information. Digital calibration is supported.
• Filter Cartridge: The sensor is protected by a Polyethylene dust filter (gray, 20 um). Periodically inspect and clean or replace the filter cartridge to ensure proper air flow to the sensor and maintain accuracy.
• Cleaning: Clean the exterior of the housing with a soft, damp cloth. Do not use abrasive cleaners or solvents.
• Firmware Update: Firmware updates can be performed via the service connector using the HW4 software.

7. Troubleshooting

If you encounter issues with your HF420 transmitter, consider the following common troubleshooting steps:

• No Output/Incorrect Readings:
  • Check power supply connections and voltage (20-28 VDC).
  • Verify wiring for analog/digital outputs.
  • Ensure the sensor probe is clean and free from obstructions.
  • Check the filter cartridge for clogging.
  • Confirm the device is not in an alarm state (programmable alarm functions).
• Communication Issues:
  • Verify cable connections for RS-485, USB, LAN, or WLAN.
  • Check communication settings (baud rate, parity, address) in the HW4 software.
  • Ensure the correct drivers are installed for USB communication.
• Inaccurate Measurements:
  • Consider recalibrating the device.
  • Ensure the operating environment is within the specified ranges.
  • Check for any sources of interference or contamination affecting the sensor.

If the problem persists after attempting these steps, contact Ace Instruments customer support for further assistance.

8. Technical Specifications

Detailed specifications for the ROTRONIC HYGROFLEX HF420 transmitter:

Figure 8.1: Visual representation of typical applications for the HF420 transmitter, including HVAC industry, greenhouses, museums, and warehouses.

9. Warranty and Support

Ace Instruments warrants this product against defects in materials and workmanship under normal use and service. The specific warranty period and terms are typically provided with the product documentation at the time of purchase. Please retain your proof of purchase for warranty claims.

For technical support, service, or warranty inquiries, please contact Ace Instruments customer service. Provide your product model number (ROTRONIC HYGROFLEX HF420) and serial number (if applicable) when contacting support.

Contact information for Ace Instruments can typically be found on their official website or on the product packaging.