Lumel HT20 Ethernet Temperature and Humidity Monitor with PoE

The Lumel HT20-2-1-00-E-1 is a wall-mounted temperature and humidity monitor with an Ethernet interface, a built-in web server and an 8 GB archive. It measures temperature and relative humidity and calculates dew point, absolute humidity, wet-bulb temperature, vapour pressure and enthalpy. The code is the version that can be powered from Power over Ethernet (IEEE 802.3af) or from the 6 V d.c. adapter that ships with it, with an English manual.

Environmental monitoring without a data logger PC

Server rooms, drug and food warehouses, laboratories, museums and glasshouses all need a record that conditions stayed inside limits. The HT20 stores readings in an internal 4 GB buffer and writes them as files to an 8 GB file system that works as a circular memory, overwriting the oldest files when full. Users read current values and trends with a browser, fetch archive files over the built-in FTP server, or collect data into a larger system through Modbus TCP/IP. Two user-defined warnings trigger e-mails, messages on the monitor web page, symbols on the display and audible alerts.

Key features from the data sheet

• Measurement of temperature, relative humidity, dew point, absolute humidity, wet-bulb temperature, vapour pressure and enthalpy.
• Ethernet 10/100Base-T with HTTP web server, FTP server, DHCP client, SMTP client and Modbus TCP slave.
• Up to 10 simultaneous connections.
• Real-time clock and periodic e-mail of measurements.
• PoE power option in the 2 supply code, 6 V d.c. adapter included in accessory code 1.

Technical specification

Measurement and interface

Supply, environment and construction

Reading the HT20 order code

The standard code is HT20 – X – X – 00 – X – X: supply (1 is 6 V d.c. only, 2 is 6 V d.c. or PoE IEEE 802.3af), accessories (0 none, 1 adapter 6 V d.c.), version (00 standard), language (P Polish, E English) and acceptance test (0 none, 1 inspection certificate, X customer request). HT20-2-1-00-E-1 therefore means PoE or 6 V supply, adapter included, standard version, English manual and an extra quality inspection certificate. The MQTT version for IoT systems is ordered as HT20IoT-2-1-MQ-E-1 and is a different product.

Installation and network setup from the manual

The monitor is fixed to a wall with screws, with the sensor facing down, and its sensor cover should not be removed. On a network without DHCP the unit starts with a default static IP address of 192.168.1.19, so a commissioning laptop is put in the same 192.168.1.x subnet to open the web page. Change the factory web-server passwords at commissioning. Allow the 15-minute preheating time before judging readings.

Where it fits in GCC facilities

In Oman and the Gulf the HT20 suits air-conditioned server rooms, pharmacy and food cold-chain storage, laboratories and museums, where an e-mail alert is wanted when humidity or temperature leaves the set band. Its -20 to 60 degrees C rating and IP20 housing are meant for indoor rooms, not outdoor kiosks.

Selection and installation notes

A wall-mounted monitor is selected from the quantities it must measure, the network it connects to and the way it is powered. Choose a location away from direct sun, heat sources and air outlets so the readings represent the room, set the IP address and the alarm limits at commissioning and check the readings against a reference instrument. Where the unit is powered over Ethernet, confirm the switch supports the PoE class required.

Information needed for a quotation

Send the full model code, the quantity, the delivery location in Oman or the GCC, the intended use and any accessories needed, so that the complete package can be quoted together.

Documents and supply information

The manufacturer data sheet is attached to this page and should be read together with the project specification and the site risk assessment before a purchase is confirmed. Ratings, standards and dimensions are quoted as printed on that sheet. Lead time, stock position and certificates available with the shipment are confirmed in the quotation, and we supply to Oman and the wider GCC region for industrial, utility and building services projects.

Frequently asked questions

Which values does the HT20 measure?

Temperature and relative humidity, plus dew point, absolute humidity, wet-bulb temperature, vapour pressure and enthalpy as calculated values.

Can the HT20 run on PoE?

Yes, the 2 supply code accepts IEEE 802.3af PoE or a 6 V d.c. adapter.

Where are measurements stored?

In a 4 GB internal buffer and an 8 GB circular file archive that can be read over the web page and FTP.

What happens when a limit is exceeded?

The HT20 sends e-mails and shows messages on its website, symbols on the display and audible alerts, using up to two defined warnings.

Does the HT20 support MQTT?

Not this code. MQTT is provided only by the HT20IoT version.

Documents and quotation

Quotations for the HT20-2-1-00-E-1 come from Seven Star LLC, independent supplier, Muscat, Oman. Provide the exact code and quantity and we confirm what can be delivered and when. The Lumel HT20 user manual is attached. Data sheet HT20-19 supplies the ordering code table and the example HT20-2-1-00-E-1 used as the product code. Verify any critical value in the maker documents. Browse Controllers & Data Acquisition too.