TABLE OF CONTENTS If the valve and sensor are properly sized and ranged, then most loops of a particular type will have similar tuning parameters. Thus, by using a table of typical values, one can start with tuning values that are at least "in the ballpark." Table 6-10 presents typical values for the four most common types of control loops: flow, temperature, pressure, and level.
| Loop Type | Gain (Prop Band) | Reset, Mins/Repeat (Repeats/Min) | Derivative, Minutes |
|---|---|---|---|
| Flow | 0.4 0.65 (150% ? 250%) | 0.25 (4 10) | None |
| Temperature | 2 10 (10% ? 50%) | 2 ? 10 (0.1 ? 0.5) | to 2.0 (always less than reset) |
| Pressure, Gas | 20 ? 50 (2% ? 5%) | May not be needed | None |
| Pressure, Liquid | 0.5 ? 2.0 (50% ? 200%) | ? 0.25 (4 ? 10) | None |
| Pressure, Vapor | 2 ? 10 (10% ? 50%) | 2 ? 10 (0.1 ? 1.0) | 0.1 to 2.0 (always less than reset) |
| Level | See text | See text | None |
| Composition | ? 1.0 (100% ? 1000%) | 10 ? 30 (0.03 ? 0.1) | Varies |
