Controllers specializes in the ways and means of control. They harness the forces around them to create... or to destroy. Controllers study why and how things stay together: they will arrange complex apparatus to maintain the unity of a thing where others might give up. They may focus their energies on the maintenance of government and the state, or on the creation and study of life.
Ti 1st emphasizes the study of life, mechanics, the animate. "I swear as the gods swear, and bring life into the void." The creation and enhancement of life is the ultimate achievement for beta Ti base EM.
Se 2nd emphasizes regulation, the actual act and architecture of control. It is the ideology of enforcement. LSI EM people have a complex relationship with the gamma side of Se, tending to measure. They strongly respect their own rights and territory, and hold little esteem for those who respect neither their own rights/territory nor those of others.
Fi 3rd is reverence for intention, especially in the name of fairness. Controllers are careful not to "jam the works", except when they must, such as to restore the balance between the two elements. This means acting with specific intent for fairness, or not acting at all. However, unhealthy incarnates of the type may attempt use the specter of negative Fi to create unfair conditions, controlling the Ti-Fi dynamic for their own purposes... particularly in the direction of destroying democracy.
Ne 4th is the valuation of ability, particularly with a sense of urgency and importance. While not as important to controllers as the maintenance and expanse of the control apparatus, they often find themselves lacking in ability when they need it most, because technology can turn the tide in no uncertain terms.
Fe 5th is a lack of patience for passions and emotions. Controllers have little energy for considering the emotional depth of others, instead preferring to "move on" to the next stage of control. This may also manifest as confusion over transmissions going unheeded, unnoticed. Little patience for palace intrigues.
Ni 6th is the sudden action, the burst of response to the popular outcry against the stifling apparatus. Just enough to get the Fe situation under control. Controllers tend to find the answers to their problems at this level.
Te 7th is the organization, the establishment apparatus the control structure surrounds and protects. The exchange system between other organizations is seen as integral and important. It is the ethical hole, the point of grey, where good and evil seem two sides of the same.
Si 8th is the point of anxiety, the vital lifeline. Is this person helpful? Will they help? What is the function, the purpose served? It is the shadowy network which seems to stretch unawares, unstoppable, inescapable. The source of nightmares and salvation.
In this description I overwhelmingly focused on the political dimension of LSI. The technical dimension is much more along the lines of the abstract terminology used by Augustinaviciute ("external statics", "fields/objects"). But you don't need to know those details to understand someone on the inside, because they only hint to their intellectual ability, not the heart.