User guide

Temperature ControlleriB6 / iB126.0 PID Controller Tuning

During the Autotune operation, the display for the selected zones blinks “Tun.” Unless you want to

terminate the Autotune by changing a zones mode, do not press any buttons during the Autotune

operation. The lower line will continue to display the setpoint you entered in Step 2.

When the controller has completed Autotuning a zone successfully, the controller will save the

tuning parameter values in the Proportional Band and Derivative (rate) parameters for all zones that

have Autotuned successfully. (The new tuning values can be viewed using the Control Config menu.)

If Autotune was unsuccessful for a zone, the zone will:

• usedefaultvaluesforPIDparameters,

• gointoalarm(redLEDlitinthe

row),

• displayitsprocessvaluealternatingwithoneofthetuningerrorcodeslistedin6.3,and

• gotoconfiguredfailsafestate;theeffectonazonesoutputdependsonhowyouconfiguredthe

Fail Safe Action parameter in the Superv [Supervisor] Config menu.

To clear the error display and put the zone(s) in standby mode, use the mode button

. (The effect

on each zones output depends on the standby configuration selections you made using the Control

Config menu.)

Fix the problem (see error code meanings in next subsection) and try tuning again.

Once Autotune has been completed successfully for all Normal zones (“NRM” mode displayed) use

the Control Config menu to disable PID Autotune.

6.3 Autotune Errors

The Autotune error codes are in the table below.

Error Code Description

Tu3

Setpoint is lower than the process value. Look at the setpoint.

If it is realistic for your process, then check the thermocouple leads; maybe they

are reversed.

Tu5

The initial process value and the setpoint are not far enough apart. For Autotune

to work, the difference must be at least 5 °C (9 °F).

Tu8

The startup curve (change in PV) was not acceptable to the Autotune algorithm.

This problem could be caused by a process upset that occurred during tuning.

Try Autotuning again when the process is stable. If the error recurs, your process

is not suitable for Autotuning. Use manual tuning as described in 6.4.

Tu9

The Autotuning timed out, because the process was unresponsive (or extremely

slow to respond). Your process is not suitable for Autotuning. Tune the

controller manually as described in 6.4.

Tun0

The Autotune operation failed for a reason other than those listed above. Try

Autotuning again when the process is stable.