X-300 | Temperature Logger and Web Thermostat

The X-300 by ControlByWeb is a powerful web thermostat, temperature logger, and temperature alarm that can be monitored and controlled over an IP network.


The X-300™ is two products in one package:

Temperature Logging

First, the X-300™ is a powerful web-based temperature logging instrument that allows you to monitor and control temperatures via an IP network. Up to 8 temperature and/or humidity sensors can be connected at a time.

Temperatures can be viewed in real-time using a web browser. In addition, the X-300™ has many advanced features including email alerts, relay control, a BASIC interpreter, and much more.

Web-Enabled Thermostat

Second, the X-300™ is a 7-day programmable web-enabled thermostat. Users can adjust and set temperatures for heating and cooling systems and view current indoor and outdoor temperatures from any web browser.

As a web thermostat, it provides an attractive control web page that works great on desktop computers as well as smartphones such as the iPhone® and other mobile digital devices.

Thermostat control web page shown on iPhone

Thermostat control web page shown on iPhone®. (iPhone® not included.)

Setup is simple; There is no app to download, no subscription to buy, no software required, and no programming necessary for setup or use.


The X-300 is versatile and has many applications. A few examples are listed below.

The X-300's powerful and flexible design make imagination its only limit.


  • Web-browser based - no software required
  • Email alerts
  • Three, independently controlled 3A relays
  • Field updatable
  • Built-In real-time clock w/ capacitor backup
  • Temperature Logger
  • Supports HTTP, TCP, SNMP, Modbus/TCP
  • Supports additional data logging and management from web services
  • Internal temperature and voltage monitoring for diagnostics
  • Wide operating temperature range
  • Removable terminal connector for convenient wiring
  • Compact, DIN-Rail mountable enclosure
  • Measurement Range: -67°F to 257°F (-55°C to +125°C)
  • Web-Enabled Temperature Logger:

  • The temperature logger can receive data from up to 8 sensors (Temperature and/or Humidity)
  • Supports BASIC scripts for advanced configuration
  • Web-Enabled Thermostat:

  • Attractive thermostat user interface
  • Connect up to 3 sensors (Indoor, Outdoor, and Humidity)
  • 7 day programming schedule
  • Connect to single stage heating/cooling system
RoHS compliant Made in the USA


Temp Monitoring/Logging

Standard configuration for monitoring and/or logging temperatures.

X-300 Standard configuration for monitoring and/or logging temperatures.

Temp Monitoring with Alarm

Basic configuration for an alarm. When the temperature crosses a specific threshold, the alarm will be turned on or off. The alarm could be an audio device such as a buzzer or bell, an indicator such as a lamp, or a functional device such as a fan or heater.

X-300 Monitoring temperatures and sounding a high-temperature alarm

Web Thermostat

Basic connection to a single stage heating/cooling system.

X-300 controlling and monitoring thermostat over the internet.

X-300 Part Numbers (Differences highlighted in green)

X-300-I+PS12-A Relays: 3 (3A 28VAC, 24VDC) Temp: 8 (One temp sensor included) 9-28VDC (One power supply included)
X-300-I Relays: 3 (3A 28VAC, 24VDC) Temp: 8 (One temp sensor included) 9-28VDC
X-300-E Relays: 3 (3A 28VAC, 24VDC) Temp: 8 (One temp sensor included) POE Class 1 (0.44 to 3.84 Watt) or 5V±5%

More Information


Where to Buy

Click "Buy Online" to view part numbers and pricing. X-300 is available in the USA and internationally and can be purchased either from us or an Authorized Distributor.


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Power Over Ethernet Solutions

Address: C17 159 Airds road,
Leumeah NSW 2564

Phone: 02 9618 0444


Antratek logo


Address: Cipalstraat 3, 2440 GEEL

Phone: 014 570 557


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Address: ZA of the Provost - 6, rue Provost - Houdan 78550

Phone: 01 34 91 90 20


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Address: Flughafenallee 26 / 6. OG, 28199 Bremen, Deutschland

Phone: +49 (0)421 53 71 433


Antratek logo


Address: Apolloweg 206, 8239 DB LELYSTAD

Phone: 0320 258 334


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Address: Unit 3 Pogson Park, Pogson Road, Sydenham, Port Elizabeth, 6001, South Africa

Phone: +27-41-451-2712


MBG/Elektronik AB logo

MBG/Elektronik AB

Address: Box 1199, 251 11 Helsingborg,

Phone: +46-42-136060


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Audon Electronics

Address: Field View, Wormald Green, Harrogate, HG3 3NJ, UK

Phone: +44 (0)1765 677425


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ControlByWeb (Buy Direct)

Address: 1681 West 2960 South, Nibley, Utah 84321

Phone: 1-435-750-5999

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