
CMC 256plus
High precision relay test set and universal calibrator
The reference for accurate signal requirements
The CMC 256plus is the first choice for applications requiring very high accuracy. This unit is not only an excellent test set for protection devices of all kinds but also a universal calibrator.
Its high precision allows the calibration of a wide range of measuring devices, including: energy meters of class 0.2, measuring transducers, power quality measurement devices and phasor measurement units (PMU).
Its unique accuracy and flexibility make the CMC 256plus ideal for protection and measurement equipment manufacturers for research and development, production and type testing.
Please note: The CMC 256plus is succeeded by our new CMC 500. The CMC 256plus will still be available. Further information can be found on the Customer Portal.


Key features
- Protection test set and universal calibrator in one device
- Testing of all relay generations – electromechanical, static, numerical, IEC 61850
- Highly accurate test signals. For meter testing: The sources are the reference – no additional reference meters are required
- Integrated network for testing IEC 61850 IEDs
- 10-channel analog measurement and transient recording functionality
Compatible operating software
Test Universe
Specifically designed for settings-based protection testing with a high degree of automation, our modular software Test Universe offers numerous functions and application-optimized test modules that save you valuable time.
RelaySimTest
With its novel and future-oriented approach our software solution for system-based protection testing, performs tests independent of relay type, relay manufacturer, and offers extensive parameter settings. It focuses on the correct behavior of the protection system by simulating realistic events in the power system.
CMControl P
Use CMControl P for quick and easy manual testing. CMControl P is available as an App for Windows PC or Windows tablet and as a dedicated front panel control device.
EnerLyzer Classic
With this software the CMC test set becomes a multifunctional measurement and recording unit. You can use EnerLyzer Classic in parallel with the software used for operating your CMC.
CMEngine
The open programming interface CMEngine enables you to integrate the CMC test sets into your own testing environment and control them within any type of application.

LLO-2 Hardware Option
This option adds additional 6 low level outputs to the CMC 256plus. The total amount of generators that can be controlled by the test set is extended from 16 to 22. The low level outputs can be used to directly test relays with low level inputs or can be used to control additional external amplifiers such as the CMS 356.
The low level outputs can simulate signals from non conventional CTs and VTs with low level interfaces. Unique is that Rogowski-coil signals can be simulated not only steady state but also for transients.
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CMC 256plus - High precision relay test set and universal calibrator
Testing meters & transducers
Testing of protection and measurement equipment
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