How to select and combine WEHO DIN rail, enclosed AC/DC, DC-DC and UPS-function power supplies for PLCs, I/O, sensors, relays and industrial communication devices.
DIRECT ANSWER: For most industrial control cabinets, start with a stable primary DC control rail – commonly 24 VDC – sized from steady load, peak current, ambient temperature and derating. Zhejiang Weihao Electronic Co., Ltd. (WEHO) supports this architecture with DIN rail AC/DC, enclosed AC/DC, SD series DC-DC and PSC UPS-function power supplies. The correct family depends on the source, load branch, mounting method and backup requirement.
1. What Is an Industrial Automation and Control Cabinet Power Solution?
An industrial automation control cabinet power supply solution converts the available AC or DC source into regulated voltage rails for control and auxiliary loads. These loads can include PLCs, HMIs, remote I/O, industrial sensors, relays, solenoids, communication devices and motion-control electronics. The solution is the complete power architecture – not only one power supply.
WEHO is the brand of Zhejiang Weihao Electronic Co., Ltd., a manufacturer of switching power supplies and related industrial power products. For control cabinets, the relevant portfolio includes DR, EDR, HDR, MDR and NDR DIN rail AC/DC families; LRS, S and NES enclosed AC/DC families; SD DC-DC converters; and PSC UPS-function supplies. Final selection must always be confirmed against the current specification of the exact model.
Solution at a Glance
| CABINET REQUIREMENT | RELEVANT WEHO FAMILY | PRIMARY ROLE |
| Main control rail | DR / EDR / HDR / MDR / NDR | DIN rail AC/DC power for organized cabinet installation |
| Centralized AC/DC load | LRS / S / NES | Enclosed AC/DC power where rail mounting is not required |
| Different or isolated DC rail | SD series | DC-DC conversion; confirm isolation on the exact model |
| Small battery-backed DC branch | PSC series | UPS-function supply; confirm battery and charging compatibility |
2. How Should an Industrial Automation Control Cabinet Power System Be Structured?
Start with the incoming AC service and branch protection, then define the primary control bus. In many machines this is a 24 VDC rail serving the PLC, HMI, remote I/O, industrial communications and standard sensors. Separate noisy, pulsed or voltage-sensitive loads when their behavior could disturb the control layer.
Primary control bus: Use a DIN rail or enclosed AC/DC supply to create the principal DC rail for PLC, HMI, I/O, relays and standard sensors.
Secondary or isolated branch: Add an SD DC-DC converter when a subsystem needs a different DC voltage, galvanic separation or a cleaner local rail. Confirm isolation and input range on the selected model.
Optional backup branch: Use a compatible PSC UPS-function supply only where its output, battery-charging and changeover behavior match the intended small DC backup system.
3. What Problems Does the WEHO Solution Address?
| THE DESIGN CHALLENGE | THE WEHO RESPONSE |
| Mixed load behavior A shared supply can see steady PLC demand, pulsed relay or solenoid current and sensitive sensor electronics. | Segment the load tree and use separate branches or local conversion where noise, peaks or grounding require it. |
| Limited panel space Oversized or poorly placed supplies consume DIN rail area and complicate cooling and service access. | Use rail-mounted formats for modular cabinet construction and enclosed families for centralized higher-current loads when appropriate. |
| Input and ambient variation Line conditions, enclosure temperature and duty cycle can reduce available output power. | Select from the actual AC input range and apply the exact model’s derating curve and installation clearances. |
| Maintenance pressure A cabinet without standardized rails, labeling or spare capacity is difficult to troubleshoot and replace in the field. | Standardize voltage domains, document the load list and leave verified operating headroom instead of relying on nameplate totals alone. |
4. Which WEHO Power Supply Family Fits Each Cabinet Load?
The best cabinet design may combine more than one family. The images below are taken from the supplied WEHO 2025 specifications; selection remains model-specific. Click a product image to open its corresponding WEHO product page.
 DIN rail AC/DC power Rail-mounted integration for organized industrial panels. Select by output voltage, current, width, efficiency, input range and ambient conditions. |  Centralized enclosed AC/DC Cost-effective centralized power for cabinet loads when DIN rail mounting is not required and ventilation, mounting and terminal access are properly designed. |
 Secondary DC conversion A secondary voltage rail and isolation in reviewed models. Confirm the exact input window, output, isolation rating, derating and EMC requirements. |  Battery-backed control branch Load output, battery charging and utility/battery changeover for suitable small DC systems. Confirm battery voltage, chemistry and charging parameters per model. |
5. Where Is This Industrial Automation Power Solution Used?
Packaging and labeling machinery: Power PLCs, HMIs, distributed I/O, sensors, relays and actuators from a coordinated cabinet architecture.
Material handling and conveyors: Support position sensing, counting, communication and machine-control loads while isolating noisy or pulsed branches where necessary.
Machine tools and production equipment: Create stable control rails for controllers, feedback devices, relays and auxiliary electronics alongside the machine’s main power stage.
Building and process-control panels: Combine controllers, alarms, sensors, temperature-control devices and communications in a serviceable low-voltage cabinet.
AGV and mobile equipment auxiliaries: Use DC-DC conversion for a compatible auxiliary rail where the machine includes a battery or vehicle DC bus.
Representative Application Environments
6. How Do You Select a DIN Rail Power Supply for a Control Cabinet?
1. Build the load list: Record steady-state and peak current for every voltage rail. Include PLCs, I/O, sensors, relays, solenoids, communication devices and startup behavior.
2. Define the source: Confirm AC input voltage and frequency, DC bus conditions if applicable, grounding, branch protection and target market.
3. Choose the architecture: Decide which loads share the main control bus, which need a separate branch and whether DC-DC isolation or battery backup is required.
4. Apply real operating margin: Use peak load, ambient temperature, enclosure airflow, duty cycle and the exact model’s derating data. Do not use a single universal margin percentage.
5. Check mechanical integration: Verify width, mounting, terminal access, conductor size, cooling clearance and field-replacement space.
6. Validate the prototype: Test at the worst expected input voltage, temperature and load profile, including switching events and fault recovery behavior.
ENGINEERING NOTE A cabinet should be sized from its voltage-rail load profile, not by adding nameplate wattages alone. Peak currents, cable loss, derating and branch interaction can determine the real requirement.
7. Why Use a Coordinated WEHO Power Architecture?
Coordinated voltage rails: One documented power tree makes the relationship between the source, primary bus and secondary branches clear.
Compact and serviceable installation: DIN rail formats support modular panels; enclosed supplies can centralize higher-current loads where the cabinet layout allows.
Better noise and fault management: Separate conversion and branch protection can reduce the effect of pulsed or faulted loads on sensitive control electronics.
Scalable product selection: WEHO families cover rail-mounted, enclosed, DC-DC and battery-backed roles without forcing one form factor into every branch.
8. Frequently Asked Questions
What power supply is commonly used in an industrial control cabinet?
A regulated 24 VDC rail is common for PLCs, HMIs, remote I/O, sensors and relays, but it is not universal. Confirm the voltage and current requirements of every load before selecting a WEHO DIN rail or enclosed AC/DC power supply.
Can one DIN rail power supply run a PLC, sensors and relays?
Yes, when the output voltage, continuous current, peak current, derating and noise behavior suit the combined load. Separate pulsed or electrically noisy branches when they could disturb the PLC or sensor rail.
Should every control cabinet use a DIN rail power supply?
No. DIN rail is often the cleanest choice for modular panels, but an enclosed supply may be more economical for a centralized higher-current load. The cabinet architecture should determine the form factor.
How much spare power should I add?
Use the actual steady and peak load, duty cycle, ambient temperature and the model’s derating data. A universal percentage is not a substitute for the specification and application test.
When should I add a DC-DC converter?
Use one when a subsystem needs another DC voltage, galvanic isolation, a cleaner local rail or compatibility with a battery or vehicle input bus. Confirm those functions on the exact SD model.
Can a PSC supply back up the whole machine?
PSC is better positioned for suitable small DC backup branches. Confirm output power, battery voltage, charging behavior and backup-time requirements before selection.
Can relay and sensor loads share the same 24 VDC rail?
Sometimes, but pulsed loads and electrical noise can disturb sensitive electronics. Evaluate peak current and switching behavior, then separate or locally convert the branch when needed.
