In modern industrial and building projects, fire detection is no longer limited to local alarm indication. Many customers need detector data to be sent to a monitoring host, PLC, BMS, SCADA or other centralized platform. This is especially important for electrical cabinets, control cabinets, UPS cabinets, telecom cabinets, box-type substations and energy storage environments.
Inside a cabinet or enclosure, abnormal smoke, temperature rise or humidity change may not be visible from outside. If the detector only gives a local alarm, the signal may be missed when no operator is nearby. By using RS485 Modbus communication, the detector can transmit monitoring information to a higher-level system, helping the project team achieve centralized supervision, alarm display and secondary data integration.
ANWETECH AT-S232 / AT-S233 is designed for this type of application. It combines smoke detection, temperature measurement and humidity measurement in one compact detector, and uses RS485 Modbus-RTU communication for system integration.
An RS485 Modbus smoke temperature humidity detector is a device that detects visible smoke and monitors environmental temperature and humidity while communicating with an external system through RS485.
RS485 is widely used in industrial communication because it is suitable for multi-device communication and engineering wiring. Modbus-RTU is a common communication protocol used by many PLC, BMS, industrial control and monitoring systems.
For cabinet fire early warning, this means the detector is not only a local smoke alarm device. It can become part of a monitoring network where smoke status, temperature data and humidity data are transmitted to a user host system for further integration or secondary development.
ANWETECH AT-S232 / AT-S233 is a photoelectric smoke, temperature and humidity detector. It is a 3-in-1 sensor designed to monitor smoke, ambient temperature and humidity conditions in small protected spaces.
The smoke detection section uses a labyrinth chamber and photoelectric signal processing technology. The detector responds to visible smoke generated by slow smouldering fires or open flames. When the ambient smoke concentration reaches the configured alarm threshold, the detector provides audible and visual alarm indication.
The key advantage for integration projects is the RS485 communication interface. Temperature and humidity data can be transmitted to the user host system through RS485 for further integration or secondary development. This makes the detector suitable for monitoring systems that require data communication instead of only dry-contact alarm output.
AT-S232 / AT-S233 uses Modbus-RTU communication protocol. The standard communication parameters are suitable for many industrial monitoring and control applications.
The communication baud rate is 9600 bps. The data format is 8 data bits, no parity and 1 stop bit. The default station address is 0x01, and the broadcast station address is 0xFE.
These communication settings make AT-S232 / AT-S233 practical for engineering projects where the detector needs to communicate with a host controller, PLC, BMS gateway or monitoring platform. For final integration, the communication address, register mapping and host system programming should be confirmed according to the final product documentation and project requirements.
The RS485 sensor wiring is simple and suitable for cabinet-level installation.
The red wire is for DC12–24V positive power supply. The black wire is the negative power line. The yellow wire is 485A, and the blue wire is 485B.
This wiring structure allows the detector to receive DC power and communicate with a host system through RS485. In a real project, wiring should always be checked according to the product label, project drawings and approved technical documentation before installation.
AT-S232 / AT-S233 provides local audible and visual alarm indication. In normal monitoring status, the red LED flashes once every 8 seconds. During smoke alarm, the red LED stays on. The built-in buzzer provides a continuous alarm sound during smoke alarm or test status.
This local indication is useful for maintenance personnel working near the cabinet. However, the stronger value of RS485 Modbus integration is that the detector can be connected to a centralized system, allowing the alarm and environmental data to be monitored away from the cabinet location.
For projects where security guards, facility operators or maintenance teams monitor multiple cabinets from a control room, RS485 integration helps improve alarm visibility and response efficiency.
ANWETECH provides two model options for different integration requirements.
AT-S233 is the RS485 output model. It is suitable when the project mainly requires communication-based monitoring through RS485 Modbus-RTU. This model is practical for systems where the host controller reads detector data through communication and handles alarm display or logic processing in the monitoring platform.
AT-S232 supports RS485 communication and relay normally open / normally closed output. This model is suitable when the project needs both Modbus communication and a local relay signal. The relay output can be useful for connecting to alarm input modules, local panels, IO modules or simple linkage circuits.
For BMS or PLC projects that only require communication data, AT-S233 may be sufficient. For projects that require RS485 data plus a relay alarm contact, AT-S232 is the better selection.
AT-S232 / AT-S233 can be used in different cabinet and small protected space applications where smoke alarm and environmental data need to be integrated.
In electrical cabinets, the detector can monitor visible smoke, temperature and humidity and send data to a host system through RS485. In control cabinets, it can support integration with PLC or industrial automation monitoring systems. In UPS cabinets and telecom cabinets, it can provide cabinet-level fire early warning and environmental monitoring.
For box-type substations and distribution cabinets, the compact detector can support monitoring in limited spaces where traditional room-level smoke detection may not provide enough cabinet-level information. In energy storage environments, the detector can help monitor smoke, temperature and humidity conditions in the protected space according to the final project design.
For BMS contractors, RS485 Modbus communication makes the detector easier to integrate into a building or facility monitoring platform. The system can display alarm status and environmental data from different cabinet locations.
For PLC and industrial automation projects, the detector can be connected as part of the equipment monitoring network. This allows the control system to read data, display alarms and support project-specific logic programming according to the site requirements.
For fire protection contractors and system integrators, AT-S232 / AT-S233 provides a compact solution for cabinet-level early warning. It can help bridge the gap between local cabinet fire detection and centralized monitoring.
When designing an RS485 Modbus detector network, the project team should confirm the communication wiring, power supply, station address, host system compatibility and final Modbus register requirements before commissioning.
The detector should be installed according to the recommended installation notes. There should be no obstruction within 0.5 m around the detector. The horizontal distance from the detector to the air-conditioning supply outlet should not be less than 1.5 m. The detector should preferably be installed horizontally, and if inclined installation is required, the tilt angle should not be greater than 45 degrees.
Regular testing is also important. A simulated fire alarm test is recommended every six months to verify that the detector works properly.
ANWETECH AT-S232 / AT-S233 is suitable for projects that require compact smoke detection and environmental monitoring with communication integration. It combines photoelectric smoke detection, temperature measurement, humidity measurement, LED indication, buzzer alarm and RS485 Modbus-RTU communication in one device.
For projects that require relay output in addition to communication, AT-S232 provides RS485 plus relay normally open / normally closed output. For projects that require RS485 communication only, AT-S233 provides a practical and compact solution.
This makes AT-S232 / AT-S233 suitable for electrical cabinets, control cabinets, UPS cabinets, telecom cabinets, box-type substations, energy storage environments and similar protected spaces.
