Monitor and log tank levels from anywhere in the world! No cloud needed!

ControlByWeb - Ethernet I/O Experts

Monitor and log tank levels from anywhere in the world! No cloud needed!

ControlByWeb’s level monitoring sensors and controllers provide a superior solution for any tank level monitoring needs. Monitor liquid levels with three different types of monitoring technologies: ultrasonic, float, and pressure. Whether you have an IBC tank, tote, or chemical injection tank ControlByWeb has the best local and remote level monitoring solution for your application.

Remote Level Monitoring & Pump Control

Pair a level sensor with a ControlByWeb controller to remotely monitor liquid levels, control pumps and valves to maintain tank levels, view log files, and send tank level information to existing monitoring systems. Program the device with our intuitive, built-in Task Builder and let the device control all logic, without needing to rely on any cloud services.

Choose the Best Sensor

Choosing the best level sensor technology for your application can be challenging, however we want to help make the selection process easy.

Monitor and log tank levels from anywhere in the world! No cloud needed!
Frequently Asked Questions

Level monitoring is the process of using technology to monitor the liquid or solid levels and volumes in industrial tanks, silos or totes. Typically a sensor is installed in a tank or container and the measurement data from the sensor is transmitted to a local display or to a network device where levels can be monitored remotely. This is particularly useful in situations where tanks may contain liquids, such as oil, fuel, or chemicals, which can be unsafe to manually check using traditional methods. Level monitoring is also useful in applications where a tank may be difficult to reach or access, and a sensor need only be installed once and then monitored locally on a display or remotely via a web browser.

Remote tank level monitoring works by connecting a level monitoring sensor to a network controller capable of interpreting measurement data from the sensor and making that data available via a network connection. Sensor data can either be accessed on a local network or remotely, depending on the desired configuration. Many network controller manufacturers require a subscription to a cloud service, however ControlByWeb controllers can be accessed directly over the network with no need for a cloud.

There are three main types of sensors that can be used for tank level monitoring: ultrasonic sensors, float switches, and pressure transducers. Choosing the right level sensor for your particular application comes down to several key factors. The first point to consider is what kind of liquid you will be measuring. Most sensors will work well in clean liquids, however if your liquid is dirty or corrosive then a float switch or pressure transducer would be better suited for the job. The second thing to consider is where the tank can be accessed to install the sensor. If the top of the tank is easily accessible then most sensors will do. If the top is not easily accessed then a pressure transducer could be a good option since it can be installed in tank vents or head pressure. Another consideration is the size of the tank. Each type of level sensor has a range of measurement that needs to be considered before choosing a sensor. The easiest way to determine which sensor will work best is to talk to one of our level monitoring experts and they can guide you through the decision-making process.

Many of our ControlByWeb devices with analog or modbus inputs work best for level monitoring. We have developed our X-404 controller specifically for level monitoring applications. The X-404 powers and communicates with the sensors via Modbus RS-485 which allows up to 32 sensors to be daisy-chained together and connected to the X-404 for the easiest installation possible for multiple tanks. The X-404 has a built-in web server with email/text notifications, logging, and an advanced task builder that allows logic to run locally on the device for controlling pumps to help maintain tank levels.

There are two types of level monitoring, point level and continuous level. Point level sensors simply measure a single preset level in the tank. Typically point level monitoring is used for an overflow line on a tank to trigger an alarm. Continuous level sensors measure the level in a tank within a given range, according to the sensor specifications. Continuous level monitoring is more robust and is useful in applications where the level of the tank needs to be measured at any given time. It is also very effective in a level management system to control pumps, valves and alarms when liquids reach specified levels within a tank.

Many controllers require a cloud service with a monthly subscription to connect and access level data. However, with ControlByWeb products, like the X-404, this measurement data can be accessed directly on the device without any monthly subscriptions. The X-404 has a built-in web server that can be accessed via port forwarding on your network router, eliminating the need for a cloud server.

Link to product pages: ControlByWeb – Ethernet I/O Experts
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WebRelay™ and WebRelay Wireless™ for Reliable Remote Relay Controlling

ControlByWeb - Ethernet I/O Experts

WebRelay™ and WebRelay Wireless™ for Reliable Remote Relay Controlling

ControlByWeb’s WebRelay provides reliable remote relay control and discrete signal monitoring over any IP network. And WebRelay Wireless has additionally “1-Wire” port for connecting up to four digital temperature or humidity sensors.

How to use WebRelay products?

ControlByWeb’s Ethernet I/O products can be used as a stand-alone device that can be integrated with an existing system.

They can also be used in peer-to-peer mode where multiple ControlByWeb products can communicate with each other, allowing you to control outputs based on another devices output or input status.

ControlByWeb’s stand-alone products can be used as slave modules to controllers such as the X-400™ / X-410™ / X-600™ Web-Enabled Programmable Logic Controller.

WebRelay™ | Single Relay and Input Module

ControlByWeb WebRelay Single Relay & Input Module

WebRelay™ provides reliable remote relay control and discrete signal monitoring over any IP network.

WebRelay can be used in countless applications, including pump and motor control, security lock systems, remote reboot, and lighting control. WebRelay’s powerful and flexible design make imagination its only limit. In addition to its built-in relay, WebRelay has an optically-isolated input that can be used to monitor the state of devices, control the relay, or control a remote relay somewhere else on the network. This feature is useful to extend the output of a PLC to another building, or to allow a switch or sensor to control a device at a distant location.

  • No programming required
  • Full control using a standard web browser or text-based XML messages
  • Can operate as a Modbus/TCP slave
  • Password protected
  • 12A relay contacts
  • ON/OFF or Pulsed relay modes
  • Optically-isolated input uses:
    • Monitoring
    • Relay control
    • Remote relay control (peer-to-peer)
  • Auto-Reboot controller mode for remote reboot of network devices
  • Selectable TCP ports
  • Removable terminal connectors included
  • DIN rail or wall-mount
  • Power supply options:
    • 9-28VDC
    • POE and/or 9-28VDC
  • Five-Year Warranty

WebRelay Wireless™ | Single Relay, Single Input, Up to 4 Sensors

The WebRelay Wireless™ is an easy to use Wi-Fi enabled relay, temperature monitor and status alerting device. The WebRelay Wireless has a built-in relay for controlling lights, motors and other relatively high current loads, a digital input which can be used to monitor and report the status of switch-closure sensors and a “1-Wire” port for connecting up to four digital temperature or other Xytronix 1-wire

The WebRelay Wireless works well as a standalone device that can be controlled using a web browser. It can be configured using simple menus and drop-down lists. It includes features such as logging, input state monitoring, and the ability to control other relays on other devices.

The WebRelay Wireless can be a selfcontained wireless access point that requires no additional servers or ControlByWeb devices. In this mode the WebRelay Wireless provides live, real-time temperatures or input status directly to a user through web browsers or the CBW Mobile app.

  • Built-in high current relay
  • Optically-isolated digital input
  • Up to 4 temperature sensors
  • Wireless Wi-Fi 802.11 b/g/n
  • Transmission range up to 250ft
  • Logging of the input, counter, temperature, humidity, relay state, and Vin
  • BASIC script support for advanced flexibility
  • Customizable web-based Control Page
  • Send email alerts (up to 8 email addresses) based on user-defined conditions
  • Supports encrypted email servers, such as Gmail
  • Static or DHCP IP address configuration
  • Real-Time clock with NTP server synchronization
  • Automatic daylight savings and leap year adjustment
  • No software required
  • XML, Modbus/TCP and Remote Services
  • Removable terminal connectors for easy installation
  • Rugged DIN-Rail/wall-mountable enclosure
  • Five-Year Warranty
ControlByWeb WebRealy Wireless Single Relay, Single Input, Up to 4 Temperature Sensors

If you need more relays (up to 16) in a single device and/or high-current (up to 30A) relays, please check product pages or give us a call:

ControlByWeb – Ethernet I/O Experts

ControlByWeb X-400™ Modular Web Enabled Industrial I/O Controller

ControlByWeb - Ethernet I/O Experts

ControlByWeb X-400™ Modular Web Enabled Industrial I/O Controller

Modular, web-enabled, industrial I/O controller that allows you to add various combinations of I/O to tailor it to your specific application. Expansion modules can either be directly connected to the X-400 through the expansion bus, or you can connect remote ControlByWeb devices through an Ethernet nework, including the Internet.

Unlimited Possibilities for Industrial Internet of Things (IIoT)

The X-400™ is a fully-featured, Ethernet I/O controller. Add up to 32 expansion modules and/or remote I/O devices for remote monitoring and control for up to 100 I/O.

Create custom logic with no scripting necessary using the X-400's intuitive Task Builder. Monitor and log sensors and control relays using the X-400's built-in web interface.

It can be controlled and/or monitored over any TCP/IP network including private networks, IP-based industrial control networks, and the Internet.

The X-400 has a built-in web server - Set up, control, and monitor using a standard web browser (or by using our CBW Mobile app). No software required, no programming necessary, and no subscription to buy.

ControlByWeb X-400 Web-Enabled I/O Controller

Peer-to-Peer Communication (P2P)

The X-400 supports peer-to-peer communication between ControlByWeb devices. The X-400 can communicate with all expansion modules and other ControlByWeb devices but offers instantaneous messaging between X-400 Series products. This means that the X-400 controller can monitor and control I/O on other X-400 Series products as if it was directly connected to the controller!

X-400™ Web Enabled I/O Controller

Custom Control/Logic

Task Builder

  • The X-400’s built-in interface allows you to create custom “Tasks” for simple and advanced control logic.
  • Easily create tasks based on inputs or outputs’ status. Create up to three actions for each task providing you with the ultimate control and monitoring solution for your application!
  • Create up to 50 Scheduled Tasks, 50 Conditional Tasks, 20 Automatic Reboot Tasks, and 20 Override Schedules.
  • The X-400 also has a built-in BASIC interpreter for more advanced or custom applications.
Conditional Tasks
  • Conditional tasks are triggered depending on an input’s or output’s status.
  • Conditional tasks are commonly used for creating email/text alerts, controlling outputs, and logging.
Scheduled Tasks
  • Scheduled tasks perform actions at preset times on specific days.
  • Scheduled tasks are commonly used to control relays or log I/O data at a specified time.
Advanced Logic

Write BASIC scripts for more advanced logic. The X-400 also includes powerful features such as, automatically rebooting devices when they become unresponsive (i.e., cameras, routers, servers, etc.).

Advanced Features


The X-400 offers the ability to log a variety of data points such as local and remote I/O, registers, and voltage. Log entries can be made at preset intervals, scheduled times, triggered by I/O changes or logic events.

Schedule a daily log file to be sent via email or uploaded via FTP server.


Graph the current log file and view the I/O’s status over time.


The X-400 supports HTTPS connections, can send encrypted emails, can communicate with remote devices using TLS.

Other Advanced Features

The X-400 has more advanced features such as the ability to initiate a connection to remote servers, BASIC programming, admin/manager/user permissions, etc.


  • Expansion Bus – Control, monitor, and log 32 expansion and/or remote modules, or up to 100 I/O
  • Secure Peer-to-Peer (P2P) Communication
  • 1-Wire Bus: Monitor up to 16 temp/humidity sensors
  • Secure, built-in web server for configuration and remote monitoring
  • User Permissions: Admin, Manager, User
  • Task Builder
    • 50 Scheduled Tasks
    • 50 Conditional Tasks
    • 20 Reboot Tasks
    • 20 Override Schedules
  • Send email alerts based on user-defined conditions (supports encrypted email servers, such as Gmail)
  • Real-Time Clock with NTP server synchronization
  • Automatic daylight savings and leap year adjustment
  • Highly configurable – Almost any combination of input/relay control possible
  • No software required
  • Customizable, web-based Control Page
  • BASIC script support for advanced flexibility
  • Data Logging
  • Graphing (logged data)
  • HTTPS/TLS encrypted
  • Static or DHCP IP address configuration
  • Modbus, SNMP, Remote Service, IP Filtering
  • Field updatable
  • Removable 14-Terminal connector for easy installation
  • Rugged DIN-Rail/wall-mountable enclosure