Automated Logic WebCTRL is a widely deployed BAS platform in commercial HVAC, and RIB® (Relay-In-a-Box®) relays from Functional Devices, Inc. are a standard switching device across fan coil, rooftop, and air handling applications on ALC systems.
If you're working with WebCTRL relay outputs on an OptiFlex controller, this guide covers practical integration: how RIB® relays wire to ALC binary outputs, how relay points map in WebCTRL, which models are the right fit for common HVAC applications, and what to check when a relay isn't responding as expected.
Automated Logic WebCTRL and BACnet Relay Output
WebCTRL is a native BACnet system. Its controllers (the OptiFlex series) communicate over BACnet/IP and use standard BACnet objects for all I/O: Binary Output (BO) for binary relay outputs, Analog Output (AO) for analog control, Binary Input (BI) for status feedback. This BACnet-native architecture means third-party devices, including BACnet-compatible RIB® relays, integrate cleanly within the WebCTRL architecture.
Note: BACnet MS/TP devices such as the RIBTW2401B-BC connect via the OptiFlex router, which handles routing between the BACnet/IP backbone and the MS/TP subnetwork.
ALC OptiFlex controllers provide binary outputs as either 24 VAC triac outputs or normally open dry contact relay outputs, depending on the controller model and output bank. Key specifications from the OptiFlex product line:
- Binary Outputs: typically configured as bussed output banks with normally open dry contact relay outputs
- Dry contact relay outputs on OptiFlex equipment controllers are low-current output contacts designed to drive control devices, not switch line-voltage loads directly. Verify the specific rating for your controller model before wiring
- Analog Outputs: 0–10 VDC for modulating devices
This is why a RIB® relay is needed. The OptiFlex binary output is a dry contact or 24 VAC control signal, not a line-voltage switching device. The RIB® relay translates that low-current control signal into a contact rated to switch line-voltage loads: fan motors, lighting circuits, damper actuators, and similar equipment.
Selecting the Right RIB® Relay for WebCTRL
The right RIB® relay for an ALC application depends on the controller's output type and the load being switched.
For 24 VAC Binary Outputs
Specify a relay with a 24 VAC coil. The coil connects directly to the controller's 24 VAC output terminal and common.
RIB2401B: 20A SPDT, 24 VAC/DC coil. The standard choice for the majority of WebCTRL relay output applications: fan coil units, VAV box control, damper actuators, exhaust fans, and lighting switching within the 20A contact rating. UL Listed as a complete field-ready assembly.
RIBU1C: 10A SPDT, dual coil voltage (10–30 VAC/DC and 120 VAC). For lighter-duty switching: damper actuators, pilot duty applications, and locations where a smaller form factor is useful. Its universal coil voltage input makes it flexible across different ALC output configurations.
RIB24P30: 30A DPDT, 24 VAC/DC coil. For higher-current loads, or applications requiring two independently switched circuits from a single ALC binary output point.
For Dry Contact Binary Outputs
A dry contact output provides a voltage-free closure; it doesn't supply power to the coil. The Dry Contact Input series of RIB relays work great for this application.
Wire the relay input circuit as follows: line voltage input power to the RIB → ALC dry contact output terminal (one side) → Wht/Red and Wht/Blu wires. When the ALC controller closes the dry contact, the dry contact input of the RIB relay recognizes the change in state and the relay coil energizes..
Please see the dry contact input RIB® relays on the Functional Devices website.
Wiring and Point Mapping Overview
Physical Wiring
Standard RIB® relay wiring for ALC binary output applications follows the same principle as any BAS relay installation:
Coil Circuit (Control Side):
- Connect the ALC binary output terminal to one coil terminal on the RIB® relay
- Connect 24 VAC common to the other coil terminal
- For dry contact outputs: wire as described above, using the Wht/Red and Wht/Blu wires instead
Contact Circuit (Load Side):
- Connect line voltage supply to the appropriate relay terminal
- Connect the load to the relay NO (normally open) or NC (normally closed) contact and Common terminal
- The coil circuit and contact circuit are completely separate; never mix coil and contact wiring
Wire Sizing:
Use wire appropriate for the coil circuit (typically 18 AWG for 24 VAC control wiring) and for the contact circuit load current. Do not exceed the relay's rated contact current for the load type (general use or pilot duty for motor loads).
Point Mapping in WebCTRL
In WebCTRL, a relay output point is configured in EIKON (the ALC programming tool) as a Binary Output (BO) or DO (Digital Output) point, mapped to the physical output terminal on the OptiFlex controller.
In the Control Program:
- The BO point drives the physical output. When the program commands the point Active (or On), the output energizes, the relay coil receives voltage, and the contacts switch
- For status feedback (confirming the load is actually running, not just commanded on), wire a current switch or status dry contact back to an ALC binary input (BI) point and map it in EIKON accordingly
- In WebCTRL's graphic interface, the relay output point appears as a binary status indicator that operators can monitor and manually override from the WebCTRL UI
For BACnet-compatible RIB® relays addressed directly on the ALC BACnet network (rather than driven by a physical output), the relay appears as a third-party BACnet device in WebCTRL. Use the Third-Party BACnet Utility in WebCTRL to discover the relay's BACnet objects and map them into the control program as network points (BBO for binary output commands, BBI for binary input status).
EIKON programming steps and WebCTRL UI paths reflect general ALC practices and may vary by WebCTRL version and controller model. Refer to current ALC documentation for your platform version before commissioning.
Common Application Scenarios
Fan Coil Unit Control
An OptiFlex equipment controller drives a RIB2401B via a 24 VAC binary output. The BO point in EIKON commands the relay on heating or cooling calls from the zone temperature loop. The relay contacts switch line voltage to the fan motor. A current switch on the load side feeds a BI input for fan proving.
VAV Box and Damper Actuator Switching
A small damper actuator on a VAV terminal draws modest current and responds to a 24 VAC signal. An RIBU1C or RIB2401B on the ALC output switches the actuator and keeps the controller isolated from the actuator's load. Spring-return actuators go to the fail-safe position when the output de-energizes—confirm the desired fail-safe position before wiring NO vs. NC.
Rooftop Unit Staging
On a rooftop unit with staged heating or cooling, each stage is a separate ALC binary output driving a separate RIB® relay. The relay contacts switch the stage enable circuit on the RTU's control board. This keeps the ALC controller's output isolated from the RTU control board voltage.
Lighting Control — Scheduled Switching
WebCTRL schedule objects drive binary outputs to RIB® relays on lighting circuits. The relay contacts switch line voltage to the lighting load. For ballasted or LED fixture loads, verify the relay's ballast contact rating—the RIB2401B is rated for electronic ballast loads at 277 VAC.
Remote BACnet Relay Point
In a large facility where running a control wire to an OptiFlex controller is impractical, a BACnet-compatible RIB® relay (RIBTW2401B-BC) is addressed on the ALC BACnet network. WebCTRL maps the relay's Binary Output object as a network point in the control program and commands it over the BACnet network via the OptiFlex router. No physical control wire required.
Frequently Asked Questions
What type of binary output do ALC OptiFlex controllers use?
OptiFlex controllers typically provide binary outputs as normally open dry contact relay outputs or 24 VAC outputs depending on the controller model and output bank. Dry contact outputs are rated for low-current control circuits; they are not designed to switch line-voltage loads directly. A RIB® relay is required to switch line-voltage equipment loads from an OptiFlex binary output.
How do I map a relay output point in WebCTRL?
In EIKON, create a Binary Output (BO) or Digital Output (DO) point and assign it to the physical output terminal on the controller. In the control program, link the BO point to the logic that determines when the relay should energize. The relay state follows the BO point value—Active (On) energizes the coil; Inactive (Off) de-energizes it.
Can I use a BACnet RIB® relay with WebCTRL?
Yes. Functional Devices BACnet-compatible RIB® relays use standard BACnet objects and integrate with WebCTRL as third-party BACnet devices. Use the Third-Party BACnet Utility in WebCTRL to discover the relay's objects and map them as network points in your control program.
What is the difference between a BO and BBO point in WebCTRL?
A BO (Binary Output) point maps to a physical output terminal on an ALC controller. A BBO (BACnet Binary Output) point maps to a Binary Output object on a third-party BACnet device—such as a BACnet-compatible RIB® relay addressed on the network. Use BO for physical outputs; use BBO when integrating third-party BACnet devices.
How do I add fan proving feedback to a WebCTRL relay output?
Wire a current switch (or status dry contact from the equipment) to a binary input terminal on the OptiFlex controller. Map it in EIKON as a Binary Input (BI) point. In the control program, use the BI point to verify that the load is running after the BO output is commanded on. Configure an alarm condition if the BI doesn't confirm status within the expected proving time.
Which RIB® relay model is best for most WebCTRL applications?
The RIB2401B—20A SPDT with a 24 VAC/DC coil—covers the majority of WebCTRL relay output applications: fan coil units, damper actuators, lighting, rooftop unit staging, and exhaust fans. It's UL Listed, prewired, and widely available through Functional Devices authorized distributors.