Product Overview
SimtoLink "IoT Smart Switch Module" is designed for remote switching and scene linkage of lighting and small electromechanical loads. While retaining local button and emergency operation, it reports status and receives commands via RS485/Modbus or wireless links. The hardware focuses on relay lifespan, surge absorption, and temperature rise control, while the firmware supports interlock, delayed closure, and power-off memory options, making it easy to interface with building automation, energy management, or user apps.
The module closes or opens one output when the agreed conditions are met. Breakers in the distribution board still handle overcurrent and short-circuit protection. Local buttons and emergency operation stay in place, so a circuit can still be switched at the cabinet if the platform is offline, an account is disabled, or a technician is already there. Orders are split by channel count, supply, and mounting: 1 to 8 channels, 220 V AC or 12–24 V DC, and DIN rail or a concealed back box are different constructions. The wiring diagram is used with the order number.
Key Parameters (Typical Configuration)
| Parameter | Specification | Notes |
|---|---|---|
| Channels | 1–8 channels | Set by order code |
| Load capacity | 16 A per channel (resistive, typical) | Capacitive and inductive loads need derating |
| Control interface | RS485 Modbus RTU | Wireless model, or dual-mode, as the alternative |
| Wireless (optional) | Wi-Fi / Zigbee | As stated in the specification |
| Power supply | AC 220 V or DC 12～24 V | Depends on the version |
| Installation | DIN rail or flush back box | Mechanical parts optional |
Typical Applications
Smart Lighting
Public-area lighting holds a set illuminance and follows time-of-day schedules, working with occupancy sensors and light meters to cut standby energy. Corridors, lobbies, and garages sit in different schedule groups. Emergency lighting stays out of any scene that can switch everything off at once, so a closing-time scene does not also switch off the evacuation routes.
Shops and Offices
A business template goes out in one action. Circuit state is checked remotely, and an unexpected open is sent to operations. The template covers signage, sales-floor lighting, and office lighting only. It does not include cold cabinets, network equipment, or the security panel. A check reads the feedback and also confirms that the last command from the platform succeeded.
Auxiliary electromechanical loads
Fans, shutters, and fresh-air units are intermittent loads, run with interlocks and run-feedback contacts. Up and down, and supply air and the related exhaust, sit in separate interlock groups. A circuit with no end-of-travel feedback only reports that the command was sent. A coil pulling in does not mean the equipment has finished moving.
Sub-metered circuits
Working with sub-meters, circuits can be opened outside working hours and under a demand policy. The shutoff list is written per circuit in advance. Metering supplies the condition for whether a limit has been crossed. The module still does the switching, and the local button stays available so maintenance can open the circuit.
Installation and Acceptance Tips
- Calculate the contact capacity and heat dissipation according to the load type. For inductive loads, it is recommended to add arc suppression or choose a solid-state solution.
- High-voltage wiring must be performed by a licensed electrician. The neutral line and PE must comply with local electrical codes.
- On first power-up, complete loop switching, Modbus register read/write, and OTA/key strategy verification.
How to group circuits without switching off the wrong loads
If lighting, fans, shutters, and fresh air share one scene that switches them all off, equipment that should keep running is easy to take down with them. Supplies for emergency lighting, exit signs, the security panel, and network equipment form their own groups and stay out of any scene that can be closed in a batch. Business lighting, sign lights, and decorative lights can sit in schedule groups. Fans and shutters that have an interlock or end-of-travel feedback form their own groups, so a lighting policy does not carry them along. Groups are fixed while the wiring is done. Scene names on the platform match the terminal numbers, for example “Level 1 public lights 1–4”, so a remote check maps to a specific circuit and the duty operator can read from the alarm which circuit opened.
Loads in one group should be as alike as possible. When every channel is resistive lighting, size the circuits from the typical resistive rating on this page, and leave margin for diversity and for ambient temperature. Once a fan, a shutter motor, or a solenoid valve is mixed in, derate that channel for its own load. Do not add the channel ratings together. Interlock is for equipment that must not run at the same time, such as shutter up and shutter down. If the interlock condition is not met, leave the output on the safe side it is already on, and accept the next command only after feedback returns. Before a scene template is sent, check each channel in the group on a single module: the name, the terminal, and whether a batch switch-off is allowed.
Which takes priority: the local button or a remote command
A local button, a schedule, and a command from the platform can all meet the same output. Priority is written into the commissioning record before go-live. A maintenance switch and emergency operation come before remote commands and schedules. A manual command on site stays in force for a set time, and the scene resumes only after that time ends. Schedules and platform scenes apply when nothing local is forcing the output. Power-fail memory is chosen per circuit: on power return, restore the state from before the outage, stay off, or run one default safe scene. Circuits tied to emergency lighting should switch on when power returns, or stay on. Business lighting can stay off after power returns and wait for a schedule or a local action. Write each circuit’s power-fail option beside the wiring diagram, so one batch of modules is not programmed with the same behavior on power return.
Delayed switch-on staggers several channels starting together, and it also leaves a gap for fans and shutters to move. Whether the delay sits in the module or on the platform depends on whether it still has to run when the network is down. Fixed periods for public-area lighting, and the basic interlock between lobby and corridor, are stored in the module. The platform sends them and reads them back. Overtime and changes to business days stay on the platform: one change edits the calendar only, and the fixed periods in the module stay as they are. While the link is down, the local policy keeps running. After the connection returns, the module reports the actual state. A button already pressed on site is kept until that manual hold ends. The platform does not overwrite that local action with an “expected state”.
Size resistive and inductive loads separately
The typical rating per channel on this page is given for a resistive load. Ordinary resistive lamps and some heating loads can be sized at that level, still leaving margin for diversity and for temperature inside the cabinet. LED drivers, long cable runs, and capacitive parts bring an inrush when the circuit closes. Fans, contactor coils, and shutter motors are more likely to draw an arc, and both contact life and temperature rise get worse. Derate those circuits, move them to a solid-state output, or add arc suppression and a suitable contactor on the load side. The final choice is made by a licensed electrician against the load on site. Tender documents list capacity by load type and state that capacitive and inductive loads need derating. The specification shipped with the unit governs.
A solid-state output has no mechanical contact and suits frequent switching. Conduction loss becomes heat, so cooling and the mounting gap have to follow the temperature inside the cabinet. A relay provides contact isolation and suits a circuit that needs a definite break. When it operates often, contact life has to be judged. Write the expected operations per day into the selection. Public-area lights a few times a day are usually within a relay. If the policy switches with every person walking past, look at the relay again or change to solid-state. A feedback contact or a current state separates “command sent” from “the load has stopped”. Fan stop and shutter end-of-travel should come from feedback on site. Coil pull-in only means the command reached the output stage. When modules sit side by side in a cabinet, leave the gap the specification asks for between them, so stacked temperature rise does not force an earlier derating.
What to check first when mapping points to the building controller
On RS485 and Modbus RTU, agree the slave address, baud rate, parity, and what each register means before any scene is configured. Coil registers are the on and off commands. Discrete inputs are the feedback. Build those two point lists separately. Writing one coil and writing several coils use different function codes. The controller point list stays in line with the module manual. One multi-coil write covers only the channels enabled on this module. During the point check, close and open each channel in turn and record the command value, the feedback value, and the real state of the lamp or the fan. Move to the next channel only when the three agree. If they do not, check the wiring and the control cable first. Scene templates wait until the point check is finished.
A wireless model and a wired model differ mainly in delay and in what happens after a dropout. Load capacity still follows the specification for that order number. WiFi or Zigbee suits a retrofit that wants fewer control cables. Plan the channel, where the gateway sits, and the local policy that continues after a dropout. A dual-mode order number states which link is used in normal running and which is the standby. Before the standby is enabled, turn off write permission on the other link so the two links do not write opposite commands at the same time. When the point list is aligned with a smart lighting policy, hand the scene names, circuit numbers, and interlock relationships to the controller side. The platform keeps the business scenes and reads status back during a check. Interlock logic stays in the module.
- After a dropout, the local schedule keeps the original policy. What is reported after the link returns is the actual state on site.
- Power-fail memory after power returns matches the safety need of that circuit. Emergency lighting and business lighting can differ.
- The local button can operate on its own while the platform is offline, and a scene does not override it before the manual hold ends.
- Power wiring is done by a licensed electrician. Neutral and protective earth follow the local code. Acceptance of the control logic is recorded apart from insulation and earthing checks.