Firmware & Software Versions

AC-PRO-II® features a USB port that allows firmware to be updated in the field, using a Windows PC and our free InfoPro-AC software.  It is important that you have the latest version of InfoPro-AC before updating AC-PRO-II®. Additional firmware update instructions are included in the InfoPro-AC Help Menu.

AC-PRO-II® Firmware

The following table lists AC-PRO-II® firmware revision history. If you would like to receive the latest firmware, please complete the request form below.

Note that your existing firmware version can be displayed on the AC-PRO-II® screen by pressing the “MORE” button when at the main readings screen.

Learn more about AC-PRO-II® and review the Instruction Manual for additional details.

Request the Latest AC-PRO-II® Firmware Here:


Trip Unit Firmware Version Highlights / Summary



  • Firmware Release Notes and FAQ
  • Scheduled Maintenance Reminder
  • Power Demand Metering (KWD/KVAD)
  • Reverse Power Protection
  • CT auto-polarity correction
  • Soft Quick-Trip control
  • Close E/O Breakers
  • Zone Block output signal
  • UnderVoltage - additional delay settings
  • Current Unbalance protection
  • LSI protection for Neutral
  • Breaker cycle counter
  • Modbus: higher baud rates & misc improvements

  • Added "special purpose" Modbus registers 7072-7076, which provide current values down to 2% (accuracy is not guaranteed below 10%)
  • Improved voltage measurement capabilities (in the event of a Ground Fault on a non-solidly grounded system - applies to AC-PRO-II with VDM only).

  • Added Phase Loss / Reverse Protection feature ***
  • Added “Test Mode” for testing convenience.
  • Added Line-to-Line Voltage measurement, and removed Line-to-Neutral voltages (for AC-PRO-II with Voltage Divider Module).
  • Improved UnderVoltage protection ***
  • OverVoltage and UnderVoltage now have dedicated pickup settings and delay settings for both Trip and Alarm features.
  • Improved Modbus Communications reliability
  • Added Ground Fault Alarm feature
  • Added Ground Fault Test trip function
  • Added Frequency Measurement
  • InfoPro-AC v2.0.36.0 or later must be used with firmware v2.0.19.0 and later.
  • ***Phase Loss / Reverse feature and improved UnderVoltage require AC-PRO-II with VDM rev 2 hardware, which is present in AC-PRO-II with VDM units shipped 2016 & later
Initial v2.0 shipped Nov. 2017


  • Added I^5t slope options to ground fault protection.
  • Line-to-Line voltage values are now available over Modbus communications. 
  • Improved Alarm relay manual reset functionality.
  • Reduced possibility of reporting incorrect breaker clearing times if limit switch is mis-wired or not wired.


  • Increased maximum CT rating from 5000A to 6300A.
  • Added capability to allow InfoPro-AC to display breaker position if limit switch is wired in. 
  • Neutral overload trip times are now based on Neutral CT secondary setting, not Phase CT secondary setting.
  • Improved trip times for low current Short Time power-up trips (power-up delay was present only in v1.7).
  • InfoPro-AC v1.1.10.0 or later must be used with firmware v1.8.


  • Misc modbus communications fixes related to status, system date/time, consistency in current scaling.
  • Improvement to clearing time measurement for low current power-up trips when using 52a or 52b (limit switch) method.


  • Added ability to fire Siemens ST II and ST III, and Westinghouse DS actuators (requires AC-PRO-II hardware version shipped after 7/1/15).
  • Addressed intermittent display flicker issue on initial USB power-up.
  • Improved OK LED error logic.  Added "Sluggish Breaker" as reason to turn OFF the OK LED.



  • Eliminated possibility of GF type being set to Return over communications (while NOL is set to ON).
  • Improved sluggish breaker screen logic when 52a or 52b limit switch is used.



  • Fixed Modbus power registers 7062 and 7068, and Quick Trip register 7103.
  • Improved compatibility with existing LCI web-page.
  • Eliminated possibility of Display being powered up before trip unit.


  • Initial AC-PRO-II firmware (first release)



ISO 9001