PEC data is stored on the motor boards in the GPS, CPC, CPC Deluxe, CGE, CGEM, CGEM DX and CGE Pro mounts in order to improve their drive accuracy. Using functions in the hand control and PECTool is sufficient for you to use periodic error correction with these mounts.However, in order for PEC to work, the data stored on the motor boards must be synchronized with the worm gear by a special indexing gear. When you power down the mount, this synchronization is lost. This is true of PECTool, the hand control’s internal playback system and programs like PEMPro because the synchronization is maintained by the mount’s hardware when the mount is on.
If you are using third party software like PEMPro, you should be aware of the following facts.
The data that a third party PEC program stores to the mount’s motor board should be valid. Once it’s stored, the mount’s connection with the program and PC is no longer necessary for PEC to work.
To use PEC playback it's necessary for the synchronization to be reestablished.
Even though equatorial tracking is on when the scope is aligned, this synchronization is not automatically started. You must turn on PEC playback by pressing MENU > UTILITIES > PEC > PLAYBACK > ON. The hand control will display a message “Initializing…please wait” during the process of using the motor controllers to synchronize the worm gear.