Why replace a good PDU if only the energy metering is outdated?

In many data centers, power distribution has grown organically over the years. Different generations of racks, different PDU brands, and in colocation environments, sometimes even PDUs selected by the customers themselves.

Technically, there need not be anything wrong with that.

A solidly constructed PDU can distribute power trouble-free for years. The challenge arises when the requirements surrounding energy metering, monitoring, reporting, power quality and integration with DCIM systems changing faster than the electrical infrastructure itself.

Then an interesting question arises:

Do you have to replace hundreds or thousands of well-functioning PDUs to get modern energy metering?

Not necessary.

The problem is not always with the PDU

When modernizing a data center, attention quickly turns to smarter rack PDUs. This is logical for new construction or when existing equipment is actually due for replacement.

The situation is different for existing installations.

The electrical distribution may still be fully adequate, even though, for example, modern communication, central monitoring, or sufficiently detailed energy data are lacking. Schleifenbauer cites basic PDUs, older intelligent PDUs, and PDUs without modern communication features as typical retrofit situations in this regard.

Complete replacement then means that the part that is still functioning properly is also replaced.

And in an operational data center, replacing a PDU is not the same as swapping out a random IT component.

Account must be taken of A and B feeds, connected equipment, change windows, redundancy, cabling, commissioning, and especially the risk of interruption.

Moreover, on a larger scale, it becomes a logistics project.

Colocation makes that problem even more interesting.

The situation can be complex, especially in colocation environments.

The data center operator is responsible for power supply, capacity, and often also for reporting and billing, while the infrastructure may be the property or responsibility of the customer beyond a certain point.

This means that an operator may have a need for better energy data, while not wanting or being allowed to replace the customer's PDU at all.

Exactly there is measure before the PDU interesting.

Instead of necessarily placing the intelligence inside the rack PDU, the measurement function can be placed in front of it.

Schleifenbauer has the Inline Meter 5.0 developed for that principle. The meter is placed between the power source and the existing PDU and measures current, voltage, power, and energy, among other things.

The existing PDU therefore remains part of the installation.

Retrofit: leave the power distribution intact and modernize the metering layer

That is a fundamentally different approach to modernization.

Not:

Out with the old PDU → in with the new intelligent PDU

but:

retain existing PDU → add modern measurement and communication layer

The Inline Meter is placed before the existing PDU in the food chain. As a result, it can also outside the rack be installed when the technical setup permits.

For data centers, this can be a significant advantage. It is not necessarily required to modify the existing rack PDU, and the existing power distribution can be retained.

That makes retrofitting interesting for, among others:

• existing data centers with a large installed base of PDUs;
• colocation with client-specific PDUs;
• basic PDUs without energy metering;
• older intelligent PDUs whose measurement or communication technology is outdated;
• phased modernization in which not all racks can be addressed simultaneously.

Schleifenbauer explicitly positions the Inline Meter for this type of retrofit and for situations where responsibilities between the data center operator and the end user are separated.

More than just measuring kWh

A modern energy meter in a data center must, of course, be able to do more than just provide a cumulative kWh reading.

Depending on the version, the Inline Meter measures, among other things, voltage, current, active power, apparent power, reactive power, energy, frequency, power factor, crest factor and Total Harmonic Distortion (THD).

The 5.0 architecture also supports modern communication and integration, including 1 Gbps Ethernet, REST API, Modbus/TCP and SNMP.

That difference is important.

After all, you are not just adding a measurement point. You are creating a new digital layer on top of an existing electrical infrastructure.

And it is precisely that layer that makes further analysis possible.

The true value emerges when all meters come together.

One meter tells what one feed does.

Hundreds or thousands of meters tell what a data center does.

Therefore, the Gateway version of the Inline Meter also includes EnerTree DCEM, the Data Centre Energy Management platform from Schleifenbauer. The EnerTree Platform runs outside the PDU in a VM or container environment and is designed for large-scale environments of up to 10,000 PDUs.

This allows measurement data to be collected and analyzed centrally instead of device by device.

EnerTree offers, among other things, real-time insight, historical data and trending, central configuration, reporting, role-based access control, and power quality monitoring capabilities. Furthermore, the information can be integrated with existing DCIM, BMS, and other management systems via open interfaces.

With that, retrofitting suddenly becomes much bigger than just:

“We want to read out a few old PDUs.”

It will be a way to undermine a heterogeneous existing electrical infrastructure one modern monitoring architecture to bring.

And then comes the software license

In a retrofit project, the hardware price is often a major factor.

However, with dozens, hundreds, or thousands of measurement points, the Total Cost of Ownership is at least as relevant.

Monitoring software can become a recurring expense when functionality depends on licenses or subscriptions.

Schleifenbauer opts for a different model with EnerTree.

EnerTree DCEM is available license-free with the accompanying Schleifenbauer hardware. Schleifenbauer itself describes the software as full DCEM functionality without subscription costs; a perpetual usage license applies to the EnerTree Platform within the organization.

That makes the business case for a retrofit different.

You are not only investing in new measurement points, but with the Gateway architecture you simultaneously gain a central DCEM platform with which that infrastructure can be managed and analyzed.

Without a separate annual software subscription, solely to maintain access to the energy data produced by your own infrastructure.

Interesting on a small scale

Suppose an existing data center has hundreds of racks with a mix of basic PDUs, older intelligent PDUs, and equipment from different generations.

Everything functions properly electrically.

But the operator wants a single modern monitoring layer for energy, capacity, reporting, and analysis.

Traditionally, such a modernization project could mean that a significant portion of the PDU-installed base needs to be replaced.

With retrofitting, the question can be reversed:

Which parts really need to be replaced and which can we make more intelligent?

If the existing PDU still performs its primary task well, namely reliable power distribution, an Inline Meter can add the missing metering and communication function.

This ensures that a larger portion of the existing investment is retained.

This not only reduces the amount of hardware to be replaced, but also limits work in operational racks and prevents functioning equipment from being written off solely due to outdated electronics or communication.

The network architecture is also part of the retrofit.

With hundreds of measuring points, a second practical problem subsequently arises: connectivity.

An energy meter is only truly useful when its data is reliably available.

The Inline Meter 5.0 uses the same modular communication architecture as the Schleifenbauer PDU 5.0 for this purpose. Depending on the application, Gateway, Controller, and Daisy Chain modules are available. The Gateway architecture is intended for central management via EnerTree; moreover, multiple units can be linked so that not every metering point requires a completely separate network connection.

That is relevant for retrofitting.

Because a solution where every extra meter requires new network cabling, switches, and IP management can create a new infrastructure problem on a large scale.

A retrofit strategy must therefore not only look at power look, but also at data.

Measuring outside the rack can actually be an advantage.

The idea that energy metering must by definition be located in the rack PDU therefore deserves reconsideration.

When the goal is to measure the total energy consumption of a rack, feed, or consumer, it can be logical to place the measurement point in a controlled position before the PDU.

Especially in a colocation environment.

The customer can retain their existing rack configuration, while the operator has a standardized measurement point at their disposal.

This neatly separates two responsibilities:

The PDU distributes the current; the Inline Meter supplies the measurement data.

That separation can be technically very valuable when different customers use different PDUs.

The operator then does not need to make every brand and every generation intelligent. The measurement architecture becomes more independent of the underlying rack PDU.

Modernizing does not necessarily mean replacing

Data centers have a long technical lifespan. It is therefore inevitable that infrastructure from different generations coexists.

The question is not whether everything is equally new.

The question is whether you have the information to properly manage that infrastructure.

When an existing PDU still functions excellently electrically but no longer meets current requirements for energy metering, communication, and analysis, complete replacement does not automatically have to be the first step.

Retrofitting makes it possible to renew the intelligence while the existing power distribution remains intact.

With the Schleifenbauer Inline Meter 5.0 modern energy metering is added before the existing PDU. With EnerTree DCEM can that measurement information subsequently be collected, analyzed, and integrated centrally, without separate recurring software licensing costs.

For existing data centers, that can be a much more interesting modernization strategy than simply replacing everything.

Retain what works well. Modernize what is outdated.

Inline Meter models

GM 47A7VIP1101 Inline Meter vertical single phase 16 A 

GM 8BCFDIP1101 Inline Meter double horizontal single phase 16 A 

GM 681DVIP1301 Inline Meter vertical single phase 32 A

GM ED23DIP1301 Inline Meter double horizontal single phase 32 A 

GM 373AVIP3101 Inline Meter vertical three phase 16 A 

GM BA4EDIP3101 Inline Meter double horizontal three phase 16 A 

GM B295VIP3301 Inline Meter vertical three phase 32 A 

GM 0A1DDIP3301 Inline Meter double horizontal three phase 32 A 

The post Why replace a good PDU if only the energy metering is outdated? appeared first on Schleifenbauer – PDUs.

Source: https://www.schleifenbauer.eu/nl/inline-meter-pdu-retrofit/