Sentera DCTHF-2
Duct sensor for temperature and humidity that controls a fan or damper through its output.
The Sentera DCTHF-2 is a duct sensor and controller that measures temperature and relative humidity in ventilation ducts and drives a fan or damper through its output. This Modbus RTU template reads temperature, humidity, dew point and alarm flags and lets you set alert limits and override the output from ModbusCloud.
- Protocol
- Modbus RTU
- Connection
- RS485, 19200 baud
- Registers
- 38, read and write
- Brand
- Sentera
- Key readings
- Temperature · Relative humidity · Dew point · Output value · Sensor alarms
- Available commands
- Alert limits · Output override · Output type · Output minimum and maximum
- Compatible models
- DCTHF-2 · DCTHG-2
- Last updated
Registers (38)
38 read, 22 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| Temperature | °C | Read | |||
| Relative Humidity | %RH | Read | |||
| Dew Point | °C | Read | |||
| Actual Output Value | % | Read | |||
| Temperature Output Value | % | Read | |||
| Humidity Output Value | % | Read | |||
| Output Control Mode | Read | ||||
| Temperature Alert Flag | Read | ||||
| Temperature Range Limit Flag | Read | ||||
| Temperature Sensor State | Read | ||||
| Humidity Alert Flag | Read | ||||
| Humidity Range Limit Flag | Read | ||||
| Humidity Sensor State | Read | ||||
| Minimum Temperature Alert | °C | Read and write | |||
| Maximum Temperature Alert | °C | Read and write | |||
| Minimum Humidity Alert | %RH | Read and write | |||
| Maximum Humidity Alert | %RH | Read and write | |||
| Minimum Temperature Range | °C | Read and write | |||
| Maximum Temperature Range | °C | Read and write | |||
| Minimum Humidity Range | %RH | Read and write | |||
| Maximum Humidity Range | %RH | Read and write | |||
| Temperature Sensor Selection | Read and write | ||||
| Humidity Sensor Selection | Read and write | ||||
| Output 1 Type | Read and write | ||||
| Output 1 Overwrite Enable | Read and write | ||||
| Output 1 Overwrite Value | % | Read and write | |||
| Output 1 PWM Voltage Source | Read and write | ||||
| Output Minimum Value | % | Read and write | |||
| Output Maximum Value | % | Read and write | |||
| Modbus Address | Read and write | ||||
| Modbus Baud Rate | Read and write | ||||
| Modbus Parity | Read and write | ||||
| Modbus Timeout | min | Read and write | |||
| Network Termination | Read and write | ||||
| Modbus Registers Reset | Read and write | ||||
| Device Type | Read | ||||
| Hardware Version | Read | ||||
| Firmware Version | Read |
Loading registers…
Send your device list
If a device is not in the library yet, we build the template for free as soon as we have the register data.
Use cases
- Show duct temperature, humidity and dew point per air handling unit on a ModbusCloud dashboard.
- Get an email when the humidity alert flag or a sensor state reports a problem.
- Keep 365 days of duct humidity history to check the effect of ventilation settings over the seasons.
- Raise or lower the alert limits remotely when the use of a room changes.
- Override the fan output from the portal during commissioning or maintenance and switch it back afterwards.
Installation
Connect RS485 A and B and 24 VDC to the sensor and run the bus to the ModbusCloud Gateway.
On the last device of the line, switch on the built-in bus termination; terminate the other end at the Gateway.
Give every Sentera device on the bus its own address; the factory default is address 1 at 19200 baud, 8E1.
In ModbusCloud, add a Modbus device with that address and settings and import the Sentera DCTHF-2 template.
Check that temperature and humidity match the air in the duct and that the output value follows them.
Things to watch for
The sensor does not answer on the bus. What should I check?
Check 24 VDC, A and B, and that address, baud rate and parity in ModbusCloud match the sensor. The factory setting is address 1, 19200 baud, 8E1. Several new Sentera devices on one bus all start at address 1, so connect them one at a time and give each its own address first.
Why does the temperature read 10 times too high?
Temperature, humidity and dew point are sent in tenths, so 235 means 23.5. The template applies the factor 0.1. If you add your own registers, use the same scale.
The output does not follow the value I write. Why?
The override value only works when output overwrite is enabled. Set the overwrite enable register to 1 first, then write the value. Set it back to 0 to return control to the sensor. Also check the Modbus timeout: when it runs out without traffic, all outputs go to their minimum.
What should I watch out for when writing settings?
A new address, baud rate or parity takes effect on the sensor, so update the Modbus device in ModbusCloud right after. Writing 1 to the register reset restores all holding registers above 10 to their defaults, including your alert limits and output settings.
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