Before you tune, you should know what you are trying to do. Are you trying to draw straight lines, ie, minimize deviations from setpoint? Perhaps there are no serious upsets and you could be satisfied with settings which would do as well as a drowsy person would do, controlling it on manual. Perhaps even, you should use averaging control, in which the object is to control as loosly as possible without the controlled variable exceeding safety limits. Heaven forbid that you are tuning just because the boss says to go out and tune that loop! Will tuning really do what you want to do?
For more information you may refer to a booklet "Controller Tuning and Control Loop Performance, a Primer" [SECOND EDITION, twice the size of the first], which is available in the US for $17, postpaid if prepaid. It has sold 29,740 copies to date. Control Engineering Magazine has referred to it as "PID Without the Math".
Information is at