Critical load data length compared to load

[cpaulgilman]

Pull Request Template

Description

Move msgbox() for load data length error messages from MIMO function in Electric Load UI form's equations to functions in UI callback so that check on load and critical load data length is triggered by on_load and on_change events on Electric Load and Grid Outage UI forms.

This change allows load and crit_load to be passed to SSC with wrong time step, so requires that we add a check in SSC to generate a simulation error when the time steps do not match. (Before this fix, the equation error prevented the user from being able to start a simulation.)

File for testing with 15-minute weather file: crit-load-timestep-test.zip

Fixes #1371

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• This change modifies variables in existing compute modules. Please see Checking for PySAM Incompatible API Changes.

Checklist:

If you have added a new compute module in a SSC pull request related to this one, be sure to check the Process Requirements.

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings