Honeywell UDC 3300 manual Values are entered and used until retuning occurs again, Retuning

Retuning	The controller will evaluate current tuning as SP changes occur. When
	retuning is required, the controller operates in automatic mode and
	identifies new tuning constants. At the point, the T appears and tuning
	values are entered and used until retuning occurs again.

TUN+PV or SP+PV (process variable disturbance)

PV tuning indications

Aborting PV adaptive tuning

The TUNE demand tuning or the SP tuning portions of these selections work as stated previously.

During process variable (PV) disturbances which result from nonlinearities, process dynamics, load changes, or other operating conditions, PV adapt tuning will occur whenever a PV disturbance of

0.3% span or larger occurs. When this condition exists, the controller monitors the process response to determine whether there has been a true process change or a momentary upset. It will take 1 and 1/2 process cycles around the setpoint before any process recognition can occur to an oscillating process.

However, if no oscillation occurs, Adaptive may alter the parameters to speed up or slow down the process response, if it determines the time to return to the SP is excessive or too fast (overshoot occurs).

For this configuration, the controller operates with only one set of tuning parameters for each loop. The second set, normally used for duplex output or for keyboard, PV or SP switching, is not used because Adaptive tune continually updates the tuning parameters based on the PV deviation.

A small t is displayed in the upper display whenever PV adapt mode is in progress. During this time, changes to the configuration parameters are permitted. Whenever the t is displayed it signifies that the process response is being monitored and this may or may not result in parameter retuning.

The selection of Fast or Normal criteria has no effect on PV adaptive tuning.

If it is necessary to stop or abort the tuning:

• Press the

MANUAL/AUTO

key to return to manual mode. This will

Error prompt accessing procedure

cause an immediate abort of tuning.

•Disable TUN+PV or SP+PV in the Accutune Set Up group at function prompt ACCUTUNE or ACCUTUN2.

When an error is detected in the Accutune process, the message AT ABORT will appear in the lower display.

In order to determine what is causing the error:

•Select ACCUTUNE or ACCUTUN2 Set Up Group.

•Access Function Prompt AT ERROR or AT ERR 2 for error prompt.

200 UDC 3300 Controller Product Manual 4/00