Installation manual

Series C Controller Configuration and Operation Manual
16-2  Athena Controls, Inc. 900M050U00
16.2 Autotuning
16.2.1 Introduction
The procedure below is used to start Autotune using the front panel of a 16C, 18C, or
25C controller. You can also use a Multi-Comm host or a MODBUS master to change
the mode, view and change parameter values, and to start Autotune for the 1ZC, 16C,
18C, and 25C models.
The Autotune operation overwrites any existing proportional band, integral, and derivative
parameter values that were previously configured. (When PID control is used, the
manual reset value is ignored.)
16.2.2 Procedure
To use the Autotune feature for temperature applications:
1. Put the controller in standby mode by pressing the key until CtrLCtrL is displayed on
the top line (after approximately three seconds) and the current mode on the lower
line. Press the or key to cycle through the modes until StbYStbY is on the
lower line. Press the key again (briefly). The display will show StbYStbY alternating
with the process value on the top line, and the setpoint displayed steadily on the
lower line.
2. Configure the controller. Quick instructions for setting up a controller to use PID
control and many of the configuration default values are in Section 3.
• For the Autotune feature to be available, at least one output type parameter must
be set to PID (see 7.2).
• For Autotune to work, the controller cannot be configured to ramp to the setpoint
at startup as described in 11.2. You do not have to disable the single step ramp
feature, but if it is enabled, set the SSrtSSrt (single step ramp time) parameter to 0
(zero).
3. Select the appropriate Autotune damping setting (see 10.2), or leave it set to the
default normal.
4. Enter the process setpoint using the and keys.
5. If possible, wait for the process to become stable (no latent energy remaining). For
heating or cooling applications, wait for the process to reach ambient temperature.
Unless the setpoint is at least 1% of supported sensor span above or below the initial
process value, the Autotune will terminate with an 05 error code (see 16.2.3).
6. Start the Autotune operation. To initiate autotuning in a 16C, 18C, or 25C controller,
press the key until CtrLCtrL is displayed on the top line and StbYStbY on the lower line.
Use the or key to display AtunAtun on the lower line. Press the key again
to start the Autotune operation.
7. Unless you want to terminate the Autotune by putting the controller in standby or
manual mode, do not press any keys during the Autotune operation. While the
controller does the Autotune, tunEtunE will alternate with the process value on the top
line. (The lower line will continue to display the setpoint your entered in Step 4.)