Carel MPX controller range showing MPXzero, MPXone and MPXpro refrigeration controllers with display terminals for retail store upgradesCarel MPX controller range showing MPXzero, MPXone and MPXpro refrigeration controllers with display terminals for retail store upgrades

What This Blog Covers

In this guide you'll learn:

  • Why CAREL introduced the new MPXPRO platform
  • The architectural differences between old and new controllers
  • Hardware and wiring changes
  • Choosing the correct replacement controller
  • Upgrading user terminals and accessories
  • Main/Secondary network considerations
  • BMS communication differences
  • Commissioning using the new Wizard
  • Common replacement scenarios
  • Frequently asked questions


Commercial refrigeration systems are expected to operate reliably, efficiently and continuously. As refrigeration technology evolves, however, many installers and maintenance engineers are now faced with upgrading ageing CAREL MPXPRO controllers to the latest generation of hardware.

To support this transition, CAREL has introduced the New MPXPRO (SPM Series), designed as the successor to the well-established MPXPRO MX30 Series controllers.

Although the new platform provides the same core refrigeration control functionality, it is not a direct clone of the previous generation.

Instead, CAREL has redesigned the controller architecture, modernised communications, simplified hardware selection and introduced a new commissioning philosophy.

For engineers, contractors and service organisations, understanding these differences before arriving on site is essential.

In this guide, we'll explain what has changed, how the replacement process works, what hardware may also require upgrading and how iACS can supply the complete range of genuine CAREL replacement controllers and accessories needed to complete the project successfully

1. Why Replace an Old CAREL Controller?

The original CAREL MPXPRO MX30 Series controllers have become one of the most widely used refrigeration control platforms across supermarkets, convenience stores, cold rooms and commercial refrigeration systems.

However, as product development continues and newer technologies become available, upgrading to the latest MPXPRO platform provides several important advantages, including:

  • Improved hardware architecture
  • Greater configuration flexibility
  • Enhanced communications
  • Simplified commissioning
  • Better long-term product availability
  • Modern software tools

Rather than simply replacing old hardware, the New MPXPRO has been developed as CAREL's next-generation refrigeration controller platform.

2. What is the New CAREL MPXPRO?

The New MPXPRO (SPM Series) is CAREL's latest programmable controller for commercial refrigeration applications.

Unlike the previous generation, where different hardware versions existed for Main and Secondary controllers, the New MPXPRO integrates these functions into a single hardware platform.

Whether operating as a Main controller, Secondary controller or stand-alone controller is now determined through software configuration rather than different hardware variants.

The controller also incorporates:

  • Integrated Real Time Clock
  • Native BMS communications
  • Simplified Main/Secondary configuration
  • Modern commissioning tools

Although the overall physical dimensions remain similar, the architecture has been completely redesigned.

Carel MPXpro DIN rail refrigeration controller with terminal blocks, USB port and green status LEDCarel MPXpro DIN rail refrigeration controller with terminal blocks, USB port and green status LED

3. Old vs New MPXPRO: What's Changed?

One of the biggest misconceptions surrounding replacement projects is that the New MPXPRO is simply a newer version of the old controller.

In reality, several significant changes have been introduced.

Simplified Hardware Architecture

Previously, Main and Secondary controllers required different hardware configurations.

The New MPXPRO removes this complexity by using a common hardware platform.

Modern Communications

The previous MPXPRO used:

  • tLAN for Main/Secondary communication
  • CAREL or Modbus for BMS communication

The New MPXPRO now uses:

  • Modbus RS485 for Main/Secondary communication
  • Modbus RS485 for BMS communication

This creates a much simpler communication architecture but also means the new controller cannot directly coexist within an existing tLAN Main/Secondary network.

More Flexible Configuration

Inputs and outputs are no longer permanently assigned.

Instead, the controller allows engineers to configure:

  • Probe functions
  • Digital inputs
  • Digital outputs
  • Analogue outputs
  • Communication settings

This provides greater flexibility while requiring more careful commissioning.

4. Choosing the Correct CAREL Replacement Controller

One of the first questions engineers ask is:

"Which replacement controller do I actually need?"

The answer depends on the existing installation and communication protocol.

For many refrigeration applications, legacy controllers such as:

can now be upgraded using the latest:

  • SPM00UNHRV030 New MPXPRO Universal Controller

For installations that continue using the proprietary CAREL communication protocol, CAREL has also introduced the dedicated spare part:

  • SPM00SUHRV030

This model has been specifically developed for legacy CAREL protocol replacement applications.

Selecting the correct controller at the beginning of the project helps minimise downtime and simplifies commissioning.

5. Hardware & Wiring Differences

Although much of the existing field wiring can be reused, several important hardware changes must be checked before power-up.

Digital Outputs

The default relay assignments have changed.

In particular:

  • Compressor output
  • Light output

Have exchanged positions.

If existing wiring is transferred without checking, outputs may operate incorrectly.

CAREL therefore recommends verifying all wiring before energising the replacement controller.

Probe Configuration

The previous controller relied on dedicated probe assignments.

The New MPXPRO instead uses configurable probe functions.

Rather than copying parameter numbers, engineers should identify:

  • Which probe performs which function
  • Which analogue input is required
  • How the function should be recreated

This functional approach provides significantly greater flexibility.

Pressure Transducers

Another improvement is support for direct connection of 2-wire 4–20mA pressure transducers.

This removes the requirement for separate external power supplies previously needed on certain installations.

6. Upgrading User Terminals & Displays

Replacing the controller often presents the ideal opportunity to upgrade the user interface.

Older installations commonly use:

  • IR00UGC300 MPXPRO User Terminal
  • IR00XGC300 MPXPRO Repeater Display

The New MPXPRO platform introduces a completely new generation of interfaces, including:

  • AX3000PS20030 Food Retail User Interface
  • AX3000PS20X10 Food Retail Repeater
  • AX3100PS20X10 Frameless Food Retail Repeater
  • S00HSA0B00S1004 Type-B Food Retail User Terminal

These newer terminals have been developed specifically for the latest MPXPRO platform and support enhanced commissioning, NFC functionality, Bluetooth connectivity and improved usability.

Communication Cables

The previous display cables cannot simply be reused.

CAREL supplies dedicated JST communication cables for the New MPXPRO, including:

  • ACS00CB0027A0 – 0.5m
  • ACS00CB000010 – 3m
  • ACS00CB000080 – 6m
  • ACS00CB002790 – 10m

Selecting the correct cable during the initial order helps simplify installation and avoid unnecessary return visits.

7. Essential Accessories for a Successful Upgrade

Depending on the existing installation, additional accessories may also be required.

These include:

MX3OP48500

RS485 and RTC module used when converting older Secondary controllers into Main controllers.

 

MX2OP48500

Alternative RS485 conversion module for compatible controller variants.

 

MX3OPSWC00

Replacement switching power supply board for older MPXPRO installations.

 

MXOPZKEYA0

Programming key used to retrieve parameter configurations from older MPXPRO controllers before replacement.

 

CVSTDUMOR0

USB-to-RS485 converter allowing connection between CAREL VPM software and legacy MPXPRO controllers.

Having these accessories available before arriving on site can significantly reduce commissioning time.

Recommended Upgrade Kit

Rather than replacing only the controller, many engineers now complete the entire upgrade in one visit.

A typical replacement package may include:

  • New MPXPRO Controller
  • User Terminal
  • Repeater Display
  • JST Communication Cable
  • Programming Key
  • USB RS485 Converter
  • RS485 Conversion Module
  • Replacement Power Supply Board

Completing the upgrade as a single package reduces downtime and helps ensure compatibility throughout the installation.

8. Main/Secondary Network Considerations

One of the most significant changes involves Main/Secondary communications.

The previous MPXPRO relied on tLAN.

The New MPXPRO uses Modbus RS485.

Because of this, the two platforms cannot coexist within the same Main/Secondary subnet.

CAREL recommends different replacement strategies depending on the installation, including:

  • Direct replacement for stand-alone Main controllers
  • Using an existing stand-alone controller temporarily
  • Converting Secondary controllers where appropriate
  • Replacing the complete Main/Secondary subnet

Understanding the existing network architecture before beginning work is essential for a successful upgrade.

9. BMS Communication Changes

The New MPXPRO communicates using Modbus RS485 as standard.

Unlike the previous platform, engineers can now configure:

  • Baud rate
  • Parity
  • Stop bits

For systems still operating with proprietary CAREL protocol, CAREL specifies using the dedicated spare-part controller version designed specifically for these installations.

Engineers should always verify the existing Building Management System before selecting replacement hardware.

10. Commissioning with the New Wizard

Commissioning has also evolved significantly.

The New MPXPRO Wizard now provides a guided setup process covering the essential parameters required to start the controller safely.

Compared with the previous generation, the Wizard now supports:

  • HMI commissioning
  • Applica Mobile
  • Applica Desktop

Once the Wizard has completed the initial configuration, CAREL recommends carrying out final optimisation using the Applica software or the supervisor platform to configure the advanced functions available on the controller.

11. Replacing a Faulty Controller

Replacing a failed controller depends on the existing system architecture.

For stand-alone controllers, replacement is generally straightforward.

Where Main/Secondary networks exist, however, engineers may need to:

  • Review addressing
  • Reconfigure Main/Secondary roles
  • Modify supervisor configuration
  • Update plug-ins
  • Reassign controller groups

Supervisor systems may also require updates to:

  • Plant Calendar
  • Floating Suction Pressure optimisation
  • Safe Restore plug-ins
  • VLSH plug-ins

to ensure the new controller is correctly integrated.

12. Frequently Asked Questions

Can I simply swap an old MPXPRO for the new version?

Not always.

Although functionally compatible, the New MPXPRO introduces changes to wiring, communications and configuration that require careful commissioning.

Can the new controller communicate on an existing tLAN network?

No.

The New MPXPRO uses Modbus RS485 and cannot directly operate within an existing tLAN Main/Secondary network.

Do I need to replace the user terminal?

In many cases, yes.

The previous user terminals and repeater displays are not compatible with the new platform.

Can I reuse my existing display cable?

No.

The New MPXPRO requires the latest JST communication cables.

Is the CAREL protocol still available?

Only on the dedicated legacy spare-part version intended specifically for CAREL protocol replacement applications.

Conclusion

Replacing an ageing CAREL MPXPRO controller is far more than simply exchanging one controller for another.

The New MPXPRO introduces a modern hardware platform, improved communications, enhanced commissioning tools and significantly greater configuration flexibility.

By understanding the changes to wiring, communications, user interfaces and accessories before arriving on site, engineers can complete upgrades more efficiently while reducing unnecessary downtime.

Planning the replacement properly and selecting the correct controller, displays and accessories helps ensure the refrigeration system continues operating reliably for many years to come.

Upgrade Your CAREL Controllers with iACS

At iACS, we stock one of the UK's most comprehensive ranges of genuine CAREL refrigeration controllers, user terminals, repeater displays, accessories and replacement parts.

Whether you're looking for:

Legacy Controllers

New MPXPRO Controllers

  • SPM00UNHRV030
  • SPM00SUHRV030

User Interfaces

  • IR00UGC300
  • IR00XGC300
  • AX3000PS20030
  • AX3000PS20X10
  • AX3100PS20X10
  • S00HSA0B00S1004

Communication Cables

Accessories

  • MX3OP48500
  • MX2OP48500
  • MX3OPSWC00
  • MXOPZKEYA0
  • CVSTDUMOR0

Our technical team can help you identify the correct replacement hardware for your refrigeration system and provide expert guidance throughout the upgrade process.

Visit the iACS Online Store today to browse our complete range of genuine CAREL controllers, user terminals and accessories, or contact our technical support team for advice before placing your order.

Upgrade with confidence. Upgrade with iACS.