A panel builder usually does not make an SMPS selection by asking only, "How many watts do I need?"

The actual question is more practical.

What voltage do the PLC, sensors, relays and transmitters require? How much current will they draw together? Are there solenoid valves or other loads that create a higher starting demand? How much spare capacity should remain for future additions? And will the power supply physically fit into the available DIN rail space without creating a heat problem?

This is where many control panel designs go wrong.

A 24 V DC SMPS may look like a simple component compared with a PLC or HMI, but almost every DC powered device in the panel can depend on it. If the supply is undersized, unstable or poorly matched to the load, several devices may start behaving incorrectly at the same time.

Radical TechMart's current Multispan Power Supplies category includes 5 V, 12 V, 15 V and 24 V DC SMPS options, including PS5, PS12, PS15, PS24 and PSW series products.

The right Multispan SMPS for an industrial control panel therefore starts with understanding the load, not simply choosing the largest available model.

What Does an SMPS Do Inside a Control Panel?

SMPS stands for Switch Mode Power Supply.

In a typical industrial control panel, the incoming supply may be AC while many automation devices require regulated low voltage DC.

The SMPS converts the available input power into the DC voltage required by equipment such as:

In simple terms, the SMPS becomes the DC power source for the control side of the panel.

That makes its selection more important than its physical size suggests.

Start With Output Voltage, Not Current

Before calculating amperes or watts, identify the required DC voltage.

The current Multispan range listed by Radical TechMart includes several voltage families:

These families are currently shown in Radical TechMart's Multispan Power Supplies collection.

For most automation panels, 24 V DC is a common control voltage, but that does not mean every device in every project operates at 24 V.

Always check the actual equipment.

A communication module may require 5 V. Another system may contain 12 V devices. Certain electronics may require 15 V.

Do not choose the SMPS voltage based on habit.

Choose it based on the load.

Calculate the Real Panel Current

Once the voltage is known, list every device that will be powered by that SMPS.

For example, consider a 24 V DC panel containing:

This does not automatically mean you should select a 3.5 A supply.

Operating continuously at the absolute limit leaves little tolerance for additional loads, startup demand, future panel modifications or variations in actual consumption.

A practical panel design should therefore include reasonable spare capacity rather than sizing the SMPS exactly at the calculated steady load.

The exact margin depends on the connected equipment and application, so use the equipment manufacturers' current consumption figures rather than relying on generic assumptions.

Why Selecting Only by Wattage Can Be Misleading

Power is calculated from voltage and current.

For a DC supply:

Power = Voltage × Current

A 24 V, 5 A supply corresponds to 120 W of DC output capacity.

A 12 V, 5 A supply corresponds to 60 W.

Both are "5 amp" supplies, but they are not interchangeable.

This is why voltage, current and wattage must be considered together.

The current Multispan PS24 listing includes versions from 24 V DC, 1 A up to 10 A, representing a broad range of power capacities for different panel loads.

The PS12 family similarly covers 12 V loads from 1 A to 8 A, with listed variants from 12 W to 96 W.

Where the Multispan PS24 Series Fits

For a conventional industrial automation panel using a 24 V DC control system, the PS24 family is a logical range to evaluate.

Radical TechMart currently lists PS24 variants including 1 A, 2.5 A, 5 A, 6.5 A and 10 A class options, depending on the listed model.

Best for: PLC panels, automation panels, OEM machines and other systems built around 24 V DC control power.

Why this series makes sense: The current range allows the panel designer to choose the supply according to actual load instead of installing one oversized SMPS in every panel.

The listing also identifies overload, short circuit, overvoltage and overtemperature protection functions, plus natural convection cooling and DIN rail or panel installation depending on the variant.

Selection caution: Do not assume every PS24 variant has identical mechanical construction, input range or other specifications. Confirm the exact model datasheet before freezing the BOM.

When the PSW Series Makes Sense

The PSW series currently includes both 12 V and 24 V DC options.

Listed versions include 24 V at 3 A, 5 A and 6.5 A, plus a 12 V 5 A version. The product page identifies DIN rail mounting, natural convection cooling and protection against overload, short circuit, overvoltage and overtemperature.

Best for: Industrial machines and control panels where a DIN rail supply with moderate 12 V or 24 V load capacity is required.

Why this series makes sense: It provides several commonly useful control panel output combinations in one product family.

Selection caution: Decide whether the application actually needs 12 V or 24 V before comparing current capacities. A PSW12 and PSW24 model solve different electrical requirements even if their enclosure looks similar.

When to Consider PS12, PS15 or PS5

Not every industrial panel is entirely 24 V DC.

The Multispan PS12 family is available for 12 V systems, with currently listed 1 A, 2 A, 5 A and 8 A options.

The PS5-2.5A provides 5 V DC at 2.5 A for lower voltage electronics and control loads.

The PS15 family is listed for 15 V DC loads with 5 A and 8 A model options. Because the current product page contains an inconsistency around the stated wattage, verify the manufacturer's latest technical documentation before final selection.

The practical rule is straightforward:

Choose the output voltage required by the equipment. Do not adapt the equipment requirement to whichever SMPS happens to be available.

Check Input Voltage Before Finalizing the SMPS

The DC output side receives most of the attention, but the AC input side matters just as much.

The PSW listing currently specifies a wide 100 V to 270 V AC input range, while individual PS12 and PS24 variants can have model dependent input specifications.

This matters when panels are installed in locations with different mains conditions or where supply fluctuations are expected.

Before ordering, confirm:

Available AC input → selected SMPS input range → required DC output

All three must match the application.

Consider the Type of Load, Not Only Total Current

A panel drawing 3 A continuously is not necessarily equivalent to another panel drawing 3 A.

A PLC, sensor and communication module combination may create a relatively predictable electronic load.

A bank of relays or solenoid valves can create more abrupt changes in current demand.

Therefore, examine which devices are connected and whether they switch simultaneously.

This is especially important in machine automation, where several outputs may energize during one operating sequence.

If the panel has significant switched loads, use their actual manufacturer data when calculating the supply requirement.

DIN Rail Space and Heat Matter

Panel designers often calculate electrical capacity correctly but forget mechanical installation.

Before selecting an SMPS, check:

The PSW and several other Multispan supplies are presented as DIN rail friendly products for industrial panels.

Natural convection also means the enclosure arrangement should allow heat to escape rather than surrounding the supply tightly with other devices.

Built In Protection Is Not a Replacement for Panel Protection

Selected Multispan SMPS listings identify functions such as overload, short circuit, overvoltage and overtemperature protection.

These features help protect the power supply and connected system under abnormal conditions.

However, an SMPS should still be treated as part of the overall panel protection architecture.

Incoming protection, wiring protection, earthing and downstream circuit protection still need to be engineered according to the actual system.

Do not assume that an SMPS with internal protection eliminates the need for proper panel protection.

Common Mistakes to Avoid

Do This, Not That

Quick Selection Checklist

Before choosing a Multispan SMPS for an industrial control panel, confirm:

1. What AC supply is available?
2. What DC output voltage is required?
3. Which devices will the SMPS power?
4. What is the current consumption of each device?
5. What is the combined normal load?
6. Are relays, solenoids or other switched loads connected?
7. How much practical spare capacity is required?
8. What SMPS output current should be selected?
9. Does the unit fit the available DIN rail space?
10. Is adequate ventilation available?
11. What protection functions are provided?
12. Is the panel ambient temperature acceptable?
13. Are additional downstream protection circuits required?
14. Has the exact model been checked against the latest datasheet?

Specifications to Confirm Before Purchase

Final specifications should always be confirmed from the latest manufacturer datasheet.

Check the input voltage range, output voltage, rated current, output power, efficiency, ripple and noise, line and load regulation, overload protection, short circuit protection, overvoltage protection, thermal protection, cooling method, operating temperature, enclosure material, mounting type, DIN rail dimensions, terminal arrangement and required installation clearance.

Why Buy Multispan SMPS from Radical TechMart?

A request such as "24 V SMPS required" is not enough information to select a control panel power supply correctly.

A better inquiry includes the incoming supply, output voltage, total current, load type, DIN rail requirement and panel environment.

Radical TechMart currently lists Multispan SMPS families covering 5 V, 12 V, 15 V and 24 V DC requirements, with multiple current capacities for industrial and OEM applications.

The focus should be to match the power supply to the panel rather than simply choosing the highest current model available.

Final Thoughts

Choosing the right Multispan SMPS for an industrial control panel is mainly a load matching exercise.

Start with the required DC voltage.

Then calculate the real current demand.

Consider switched loads, future additions, physical panel space, ventilation and input supply conditions.

Only after these points are clear should you compare PS5, PS12, PS15, PS24 or PSW models.

The correct SMPS is not necessarily the biggest one in the catalogue. It is the supply that can power the connected control system reliably while fitting the electrical and mechanical design of the panel.

FAQs

1. What is an SMPS used for in an industrial control panel?

An SMPS converts the available input supply into regulated DC power for devices such as PLCs, sensors, transmitters, relays, controllers, HMI units and communication modules.

2. Which Multispan SMPS should I use for a 24 V PLC panel?

Start by calculating the total 24 V DC current required by the PLC and every other connected load. Multispan's current PS24 and PSW ranges include several 24 V DC current capacities. Select the model only after calculating the total load.

3. How do I calculate SMPS current for a control panel?

Add the maximum current requirements of all devices powered by the supply. Then consider the characteristics of switched loads and suitable spare capacity rather than selecting a unit that exactly equals the calculated normal load.

4. Can I use a 10 A SMPS when my panel consumes only 2 A?

Electrically, a load draws the current it requires, but using a substantially oversized power supply may increase cost, panel space and unnecessary capacity. Selection should be based on the application, future expansion and panel design.

5. What is the difference between the Multispan PS12 and PS24 series?

The main distinction is output voltage. PS12 models are intended for 12 V DC loads, while PS24 models provide 24 V DC. Each family also includes different current capacities.

6. Does Multispan offer a 5 V SMPS?

Yes. Radical TechMart currently lists the Multispan PS5-2.5A, providing 5 V DC at 2.5 A.

7. What protection should an industrial SMPS have?

Depending on the model, useful protections include overload, short circuit, overvoltage and overtemperature protection. Confirm the functions and recovery behavior from the exact model datasheet.

8. What information should I provide when requesting an SMPS quotation?

Provide the incoming voltage, required DC output voltage, total load current, connected equipment, preferred mounting style, available panel space and any important environmental or protection requirements.