Edwards EST SIGA modules are the backbone of Edwards addressable fire alarm systems. Whether you are troubleshooting a module fault, replacing a failed unit, or expanding an existing system, understanding the differences between the SIGA-CT1, SIGA-CT2, and SIGA-CR is essential. This guide covers each Edwards EST SIGA module in detail, including use cases, wiring considerations, and where to source replacements.
The Edwards EST SIGA Platform: An Overview
The SIGA (Signature Series) platform is Edwards EST’s line of intelligent addressable devices for use with the EST3, iO64, iO500, and compatible Edwards fire alarm control panels. SIGA devices communicate on the Signature Data Circuit (SDC) loop, providing individual device identification, status reporting, and bidirectional communication with the panel.
SIGA modules are used to monitor and control non-detector devices: doors, dampers, sprinkler flow switches, tamper switches, fans, and other building systems. Choosing the right module type depends on whether the application requires monitoring an input, controlling an output, or both.
SIGA-CT1: Single Input Module
The SIGA-CT1 is a single-channel input module designed to monitor one supervised Class B input circuit. It is used to connect conventional (non-addressable) initiating devices to a Signature Series addressable loop. Common applications include:
- Monitoring a zone of conventional smoke or heat detectors
- Connecting a waterflow switch or pressure switch to the addressable loop
- Monitoring a tamper switch on a sprinkler valve
- Interfacing a single conventional input device where an addressable point is needed
The SIGA-CT1 provides one addressable point on the SLC loop and reports normal, alarm, and trouble states to the panel. It requires a SIGA-SB or SIGA-SB4 mounting base.
SIGA-CT2: Dual Input Module
The SIGA-CT2 provides two independent monitored input circuits on a single addressable address — consuming two points on the SLC loop. It is functionally similar to two SIGA-CT1 modules but in a single package, which makes it cost-effective when multiple inputs are needed in the same location. Typical applications include:
- Monitoring two separate sprinkler zones (flow and tamper) from one device location
- Connecting two conventional initiating device circuits where space and wiring runs favor a single module
- Pairing a waterflow switch with a supervisory switch at the same riser location
Each input on the SIGA-CT2 is independently supervised and reports its own status to the panel. Both inputs share the same physical address but appear as separate logical points in the panel’s device database.
SIGA-CR: Control Relay Module
The SIGA-CR is an output control module with a form-C relay. It is used to control building systems in response to fire alarm commands from the panel. The relay is rated for 2 amps at 30 VDC or 0.5 amps at 120 VAC. Common SIGA-CR applications include:
- Releasing magnetic door holders
- Shutting down HVAC equipment or closing fire/smoke dampers
- Activating elevator recall
- Controlling suppression system release circuits
- Activating auxiliary notification appliances not on the NAC
The SIGA-CR is programmed at the panel to respond to specific alarm conditions, and its relay status is reported back to the panel for supervision. This makes it more capable than a standalone relay panel — the system knows whether the relay actually activated.
SIGA-SB: The Standard Detector Base
All SIGA input and control modules require a mounting base. The SIGA-SB is the standard surface-mount base compatible with the SIGA-CT1, SIGA-CT2, and SIGA-CR. It provides the electrical connection to the SLC loop and mounts to a standard electrical box. The SIGA-SB4 (four-inch base) is also available for installations requiring a larger mounting footprint.
Wiring Basics for SIGA Modules
SIGA modules are wired on the Signature Data Circuit (SDC) loop using Class A or Class B wiring topology. Key wiring considerations:
- All SIGA devices share the same two-wire SLC loop; polarity must be maintained throughout.
- End-of-line resistors are required on Class B supervised input circuits connected to the CT1 and CT2.
- The SIGA-CR relay wiring is separate from the SLC loop — the control output wires connect to the relay terminals on the module, not the SLC terminals.
- Never exceed the maximum SLC loop loading — consult the panel’s installation manual for maximum device counts per loop.
Where to Order Edwards EST SIGA Modules
Life Safety Consultants stocks Edwards EST SIGA modules for immediate shipment. Browse our complete Edwards EST parts catalog for the full line of SIGA devices, bases, and accessories.
Summary
The SIGA-CT1 monitors one input circuit, the SIGA-CT2 monitors two, and the SIGA-CR controls an output relay. All three require a SIGA-SB mounting base and are compatible with Edwards EST3, iO64, iO500, and compatible panels. For replacement modules and accessories, Life Safety Consultants is a reliable source with current inventory.
