What Is a PLC Power Module? Types and Selection Criteria

A PLC power module is a supply module that provides operating power or extra supply to the modules in a PLC rack or I/O station and works only with its own series.

A PLC power module is a supply module that fits into a PLC rack or input/output (I/O) station and powers the electronics of the CPU and modules (bus or module supply) or the field inputs and outputs (I/O or field supply), and it works only with its own series. Unlike a panel-mount 24 V DC power supply, it distributes energy to the modules through the PLC rack backplane or the station's internal supply line.

Types

• Rack power supply (Schneider Electric Modicon M340/X80): Fits into the rack's power supply slot and powers the modules in the rack. There are mains-supplied BMXCPS2000 and BMXCPS3500 (100–240 V AC) and DC-supplied, isolated BMXCPS2010 (24 V DC) and BMXCPS3020 (24–48 V DC).
• Distributed I/O power module (Schneider Electric Edge I/O NTS): NTSPFB1002HK provides both bus and field supply, NTSPFD1002HK provides field supply only; both are Hardened versions for harsh environments.
• Auxiliary power supply module (Delta Electronics): Inserted as an additional supply point when the number of modules in a station grows. The AX-5 series has AX-502PS11-0A for module supply (24 V DC, 2 A) and AX-510PS12-0A for I/O supply (24 V DC, 10 A); the R1 series has R1-C02PS10-0A with 24 V DC input and 5 V DC 2 A output.

Selection criteria

1. Series compatibility: A power module works only in its own PLC or I/O series; Modicon M340/X80, Edge I/O NTS, Delta AX-5 and R1 modules are not interchangeable.
2. Supply type: If the panel has only mains, choose AC-input BMXCPS2000 or BMXCPS3500; with 24 V DC distribution choose BMXCPS2010; in DC installations up to 48 V DC choose BMXCPS3020. Delta auxiliary power modules are supplied with 24 V DC, which a separate panel-mount power supply produces.
3. Power budget: The total consumption of the modules in the rack or station must not exceed what the power module can deliver. Calculate the total with the consumption values in the series installation manual; if it is close to the limit, choose the more powerful model (BMXCPS3500 instead of BMXCPS2000, BMXCPS3020 instead of BMXCPS2010) or an auxiliary supply module.
4. Side to be supplied: In Delta AX-5 the module electronics and the I/O line are supplied separately; choose AX-502PS11-0A or AX-510PS12-0A depending on which side falls short. In Edge I/O NTS, NTSPFB1002HK fits when bus and field supply are both needed, NTSPFD1002HK when only field supply is needed.

Common mistakes

• Mistaking an auxiliary power module for a panel power supply: Delta auxiliary power modules are not connected to the mains; they are supplied with 24 V DC and distribute or convert this voltage within the station.
• Adding modules without calculating the power budget: Every module added to a rack or station raises consumption; once the budget is exceeded, modules may run unreliably.
• Mixing up AC- and DC-input models: Connecting mains voltage to a 24 V DC input module destroys it.
• Strengthening only the module supply: Output loads draw from the I/O supply; if the I/O side is short, a module supply module does not solve the problem.

Brands in the catalog

The Power Modules category has 9 active products:

• Schneider Electric 6: BMXCPS2000, BMXCPS2010, BMXCPS3020, BMXCPS3500 (Modicon M340/X80 rack power supplies), NTSPFB1002HK and NTSPFD1002HK (Edge I/O NTS)
• Delta Electronics 3: AX-502PS11-0A, AX-510PS12-0A (AX-5) and R1-C02PS10-0A (R1)

The input, output and communication modules of the same series are in the PLC Input and Output Modules category.

Frequently asked questions

What is the difference between a PLC power module and a 24 V DC power supply?

A 24 V DC power supply produces DC voltage for the panel from the mains and can power any device. A PLC power module fits only into the rack or station of its own series and distributes energy to that series' modules.

What is the difference between BMXCPS2000 and BMXCPS3500?

Both are Modicon rack power supplies fed with 100–240 V AC; BMXCPS3500 delivers more power and is chosen for racks with many modules. The total consumption of the modules in the rack decides which one is enough.

When is an auxiliary power module needed?

When the total consumption of the modules added to a station exceeds what the existing supply can deliver. The position and number of auxiliary modules are set by the power calculation in the series installation manual.

What is the difference between the module and I/O auxiliary power supplies in Delta AX-5?

AX-502PS11-0A powers the module electronics (24 V DC, 2 A). AX-510PS12-0A carries the supply for the input and output circuits (24 V DC, 10 A).