Sentera RSTHM-2
Room transmitter for temperature, humidity and light, powered over its Modbus cable.
The Sentera RSTHM-2 is a room transmitter that measures temperature, relative humidity and ambient light and is powered over its Modbus cable. This Modbus RTU template reads temperature, humidity, dew point, light level and alarm flags and lets you set alert limits and light levels from ModbusCloud.
- Protocol
- Modbus RTU
- Connection
- RS485, 19200 baud
- Registers
- 34, read and write
- Brand
- Sentera
- Key readings
- Temperature · Relative humidity · Dew point · Ambient light · Active or standby · Sensor alarms
- Available commands
- Alert limits · Light levels for active and standby · LED brightness
- Compatible models
- RSTHM-2
- Last updated
Registers (34)
34 read, 17 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 | |||
| Ambient Light | lux | Read | |||
| Active Standby State | Read | ||||
| Temperature Output Value | % | Read | |||
| Humidity Output Value | % | 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 | ||||
| Ambient Light 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 | |||
| Active Light Level | lux | Read and write | |||
| Standby Light Level | lux | Read and write | |||
| LED Indication | Read and write | ||||
| LED Brightness | % | Read and write | |||
| Modbus Address | Read and write | ||||
| Modbus Baud Rate | Read and write | ||||
| Modbus Parity | 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 temperature, humidity and dew point per room on a ModbusCloud dashboard.
- Get an email when a room stays too humid or a sensor reports a fault.
- Use the active or standby state to see when rooms are in use over 365 days of history.
- Change the alert limits of a room remotely when its use changes.
- Compare room humidity with the ventilation settings to check demand controlled ventilation.
Installation
Connect the transmitter with an RJ45 Modbus cable that carries 24 VDC Power over Modbus, and run A and B to the ModbusCloud Gateway.
Switch on the built-in termination on the last device of the line and 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 RSTHM-2 template.
Check that temperature, humidity and light level match the room.
Things to watch for
The transmitter has no power or does not answer. What should I check?
The RSTHM-2 takes 24 VDC from its RJ45 Modbus cable, so check that the cable carries the Power over Modbus supply. Then check A and B and that address, baud rate and parity in ModbusCloud match the factory setting of address 1, 19200 baud, 8E1, or the values you set.
Why does the light state stay on Low light intensity?
The transmitter reports Active above the active light level and Standby below the standby level. Between the two it reports low light intensity. Set both levels to match the room, for example 100 lux and 10 lux.
Several transmitters on one bus do not all show up. Why?
New Sentera devices all start at address 1. Connect them one at a time, give each its own address over Modbus, and add each one in ModbusCloud with its own address.
What should I watch out for when writing settings?
A new address, baud rate or parity takes effect on the transmitter, so update the Modbus device in ModbusCloud right after. Writing 1 to the register reset restores all holding registers to their defaults, including the address and your alert limits.
More Sentera templates
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