Overview
ScanImage requires an initialization (INI) file, usually named standard.ini, to be selected at startup. This file specifies & initializes all the state variables for the ScanImage configuration and determines which variables are associated with configuration (CFG) and user (USR) files. Typically there is only one INI file per ScanImage installation (a 'rig'). A subset of Rig Configuration variables are demarcated at the beginning of the INI file; these copmrise the variables that typically require modification for a new ScanImage installation. Rig Configuration variables are not associated with either CFG or USR files and are not modified during ScanImage program operation. Typically only one INI file is required per rig.
ScanImage r3.5 introduces some changes to the way INI files are handled. Please familiarized yourself with Initialization (INI) File Handling.
In addition, the variables in the Rig Configuration section have been modified, as described in the following section.
Rig Configuration Variable Reference
The INI file contains a large number of variables. Only a small number of these typically require adjustment for a ScanImage installation to a new rig. These Rig Configuration variables are clearly grouped at the beginning of the standard_model.ini file. Users should adjust these values to match the hardware and experimental requirements for their rig, to create their own standard.ini file.
The INI file parser is whitespace sensitive. The format <VARNAME>=<VARVALUE> must be strictly followed, i.e. no space to left or right of the equal sign
The standard_model.ini file contains comments which document the meaning of each of the variables. As additional support, this section serves as a reference point for the new and notable Rig Configuration variables.
triggerLineIndex: (Previously below Rig Configuration section) Allows specification of the static digital output line used as shared trigger source for acquisition, mirror, and Pockels cell board(s). The use of Port 0 on the board specified by triggerBoardIndex is assumed.
triggerInputTerminal: See External Triggering and Trigger Simplification.
externalTriggerInputTerminal: See External Triggering and Trigger Simplification.
externalTriggerTimeout: See External Triggering and Trigger Simplification.
outputBoardClockTerminal: See Clock Synchronization for more details.
maxBufferedGrabTime: Specifies max duration, in seconds, of an acquisition (effectively limiting the max number of frames) to allow without using 'SaveDuringAcquisition' option. This value should typically not be altered. Longer acquisitions should employ the new Continuous Disk Logging feature.
maxFlybackRate: This value is reserved for r3.6.
scanOffsetX/Y: (Previously below Rig Configuration section) Specify offset voltages for mirror command signals. These variables are unique among the Rig Specific variables in that they can be altered during ScanImage operation. See Beam and Scan Alignment Tools for more information.
parkAmplitudeX/Y: (Previously below Rig Configuration section) Specify voltages for X/Y mirror when parked. 
Beam safety should be considered in setting these values.
maxAmplitudeX/Y: Specify max voltage allowed for X/Y amplitudes. This clamps the sum of the scan amplitude and the scan shift set in ScanImage, for each dimension.
Shutter Variables_
The separate values for 'open' and 'closed' have been removed. Variables open and epiShutterOpen are sufficient to specify 'polarity' of shutter interface.
shutterBoardIndex: See Shutter output line(s) can be on any board.
Motor Variables
The number of variables in the rig-specific motor section has been greatly reduced. Two variables, firmware and posnResolution, are new in r3.5. See MP-285 Interface Improvements for details.