Control Gain
Control gain is the coefficient by which the error is multiplied as it is turned into the output, and it determines how aggressively the system will react. High gain produces a fast but oscillation-prone system, low gain a stable but slow-reacting one. The right value is always the balance between these two.
The practical method used in the field for setting it is this: increase the gain step by step, find the point where a regular oscillation starts in speed or position, then come down noticeably below that value. A system left at the oscillation limit goes unstable when the temperature, the oil viscosity or the load changes.
- Fix the mechanics before increasing the gain. A seized joint or a cable with slack cannot be compensated for with gain; it only brings the oscillation forward.
- Gain is considered together with deadband and ramp time; the three of them adjust different aspects of the same behaviour.
On the GS740-3P the control parameters are factory set and no gain adjustment is offered for the field. So when you see unstable behaviour, the place to look is not the parameters but the mechanics: cable tension, routing, guide firmness and joint free play.
Context in which this term is used: Electronic speed and throttle control on a diesel engine