MX250 Microprocessor Controller

MX250 Microprocessor Controller Standard Equipment


  • UL, CSA and IEC listed
  • Ringing wave immunity per IEEE 472(ANSIC37.90A)
  • Conducted and Radiated Emissions per EN55022Class B (CISPR11) (Exceeds EN55011 & MILSTD461 Class 3)
  • ESD immunity test per EN61000-4-2 Class B(Level 4)
  • Radiated RF, electromagnetic field immunitytest per EN61000-4-3 (ENV50140) 10v/m
  • Electrical fast transient/burst immunity test perEN61000-4-4
  • Surge immunity test per EN61000-4-5 IEEE C62.41
  • Conducted immunity test per EN61000-4-6(ENV50141)
  • Voltage dips and interruption immunity EN61000-4-11

User Friendly Operation

  • Multipurpose display: LEDs for continuous monitoring of switch position and source availability; a four line by twenty character LCD display for settings, functions, programming and annunciation
  • Through-the-door programming and display
  • Simplified keypad entry – menu-driven system is designed for ease of use
  • Built-in diagnosis with displays for ease of troubleshooting
  • Weather and tamper resistant touchpad

Additional Features

  • Built-in programmable exerciser uses separate microcontroller with independent battery back-up to serve as clock/calendar – battery failure will not affect switch operation
  • User settings are unaffected by power outages
  • Separate line voltage components for controller isolation
  • Inputs are optoisolated for high electrical immunity to transients and noise
  • Built-in electrical operator protection
  • Watchdog circuit for microprocessor operation
  • Source connection and transfer data logging

Select Units


The MX250 microprocessor is standard with the entire CTS product family. The MX250 Series includes all the standard features of the MX150 Controller while offering expanded programmability and field adaptability. The high reliability and ease of unattended operation makes it ideal to use in a wide range of mission critical applications.

Technical Summary

  • Rating Range Switch Dependent Switch Dependent
  • Transfer Type Application Dependent Application Dependent
  • Switch Type Application Dependent Application Dependent

Controller Specifications

  • Undervoltage Dropout for Source 1 and Source 2 75-98% of nominal 75-98% of nominal
  • Undervoltage Restore for Source 1 and Source 2 85-100% of nominal 85-100% of nominal
  • Underfrequency Dropout for Source 1 and Source 2 90-100% of nominal 90-100% of nominal
  • Delay for Engine Cool Down (U) 0-60 minutes 0-60 minutes
  • Delay Transfer to Nonpreferred Source (W) 0-5 minutes 0-5 minutes
  • Delay NeutralTransition Time Delays (DT,DW) 0-10 minutes 0-10 minutes
  • Storage Temperature (-30˚C - 75˚C ), -22˚F - 167˚F (-30˚C - 75˚C ), -22˚F - 167˚F
  • Operating Temperature Ambient 40 - 400 amp molded shell (-20˚C to 65˚C) , -4˚F to 149˚F
    40 - 4000 amp all others (-20˚C to 60˚C), -4˚F to 149˚F
    40 - 400 amp molded shell (-20˚C to 65˚C) , -4˚F to 149˚F
    40 - 4000 amp all others (-20˚C to 60˚C), -4˚F to 149˚F

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