Terminal Connections

The relay contacts are isolated from all other circuits on the module. The screw terminals are internally connected directly to the relays with no internal fuse or other over-current protection. 

The types of terminals you’ll see in one of our devices are: 

• Common (C) 
• Normally-Closed (NC)
• Normally-Open (NO) 

Connecting Large Electrical Loads 

For loads greater than a relay’s specifications, an external interposer relay should be used.

The illustration below shows how a 15-Amp motor can be controlled using an external relay. In the example, the X-410’s 1-Amp relay controls the external relay, and the external relay controls the 15-Amp load. 

Controlling a Relay contact with ControlByWeb Modules 

On our modules, you can control the relays with the built-in web browser interface and configure them to turn on/off/pulse based on conditions like time intervals, status of analog or digital sensors, timers or other programmable logic. 

Wiring Connections

The terminals for digital inputs vary slightly between models, but most include:

• Input terminal(s) 
• Ground (GND) 
• (Optional) Pull-up resistor setting 

Digital inputs on most 400 Series modules are optically isolated, helping to protect the internal electronics from voltage spikes or grounding issues. Some (like the X-420) use non-isolated inputs with shared ground for compact designs.

Electronically and Optically Isolated

Each digital input monitors the voltage across two terminals:

• Input+
• Input–

When the voltage between these terminals rises above a threshold (typically >3.5V), the input registers as ON. Below ~1.5V, it registers as OFF. Anything between is treated as undefined.

On most ControlByWeb modules (like the WebRelay, X-408, and X-12s), the input circuits are optically isolated, which protects the system from surges, ground loops, and noisy field signals.

Detecting Input States 

Digital inputs are monitored through the built-in web interface, which clearly displays each input’s ON/OFF state. You can also configure digital inputs to trigger actions, such as: 

• Turning on a relay 
• Sending email or text alerts 
• Logging events 
• Triggering conditional logic with timers or sensor values 

Wiring Connections 

Each analog input channel can be configured as single-ended, differential, or 4–20mA current loop. Wiring varies slightly by module, but most analog-capable devices include: 

• AINx+ – Positive signal input 
• AINx− – Negative signal input (for differential mode) 
• AGND – Analog ground 
• Vref – Optional 5V excitation voltage 

2. 4–20mA Mode 

• Enables internal precision 200Ω shunt resistor 
• Automatically scales A/D to ±5V 
• No external resistor needed 
• Perfect for industrial current-loop sensors (e.g., pressure, flow, distance) 

3. Differential Mode 

• Measures voltage difference between two analog inputs 
• Great for sensors with two signal outputs (like Wheatstone bridges) 
• Supports up to ±20.48V differential, with absolute input limits of ±10V 
• Requires a shared ground connection to maintain common mode range 

Configuration & Scaling 

Analog channels are configured in the web interface, where you can: 

• Choose voltage range or current mode per channel 
• Enter slope and offset to convert raw data to meaningful units (e.g., °C, psi, ft, etc.) 
• View real-time readings 
• Set conditions for triggering relays or alerts 

Example: To measure 0–20 Amps with a transducer outputting 0–5V: Slope = (20 Amps – 0 Amps) ÷ (5V – 0V) = 4 Amps/V

Wiring Connections 

Analog output wiring is straightforward and requires two terminals per channel: 

• AoutX – The voltage or current output 
• COM – Analog Ground (isolated from power ground)

However, ensure that output wiring and load resistance are within limits: 

• Max voltage output current: 10mA 
• Max resistance for 4-20mA loop: 575Ω  (based on 11.5V output headroom) 

Built-in Scaling and Control 

The X-417 includes an internal digital-to-analog converter (DAC) that automatically converts user-defined values to output signals. This means: 

• You enter values in real-world units (e.g., 0–100%) 
• The X-417 calculates and outputs the corresponding voltage or current 
• You can bypass scaling if you prefer to control via raw Modbus values from a PLC 

You can also: 

• Control outputs manually from the web interface 
• Use logic or tasks to automate changes 
• Set output values via Modbus/TCP or SNMP 

Wiring Connections 

A 1-Wire bus requires three connections:

• +5V (Power)
• GND – (Ground)
• DATA – (Shared signal line)

Multiple sensors can be daisy-chained along the same bus.

Each sensor has a unique ID, and the connected 400 Series module automatically detects each one in the on-board interface.

Monitoring & Control

Sensor data is visible directly in the module’s web interface and can also be:

• Scaled
• Logged over time
• Used to trigger relays, digital outputs, or alerts

Accessed via Modbus, SNMP, or HTTP for third-party integration

This information can then be used in the Task Builder with scheduled, conditional, or advanced logic to automate climate control systems or fan/heater activation.