-
11 -
5-2. AT (Auto tuning)
(1) Execution of AT action
•
Auto tuning function is prepared for suitable control by using PID control action with constants of P: proportional band, I: integral time and D:
derivative time calculated for PID control which are automatically stored in the internal memory.
•
By pressing the
or
key AT action control screen,
display on lower row turns into
and the point of the least digit starts flashing,
then the LED for AT monitoring turns on to indicate AT standby. Press
key to start AT action with point going off and LED for AT monitoring
flashing.
•
During AT execution, PID constants are defined by calculation for ON/OFF action (100%/0%) output for the measuring value increase and decrease
around the set value and store internal memory. Control action according to stored PID constant is started. Then the LED for AT monitoring goes
off and the display on the AT action control screen is changed to
.
(2) Abort of AT
To abort the AT action, by showing the AT action control screen, press the
or
key to select
and press
key to abort AT and LED for
AT monitoring also goes off.
NOTE: When the AT action is aborted, each value for PID is not changed.
(3) AT unable for following conditions.
•
The proportional band is "
" setting (ON/OFF action). (No AT screen is shown.)
•
Lock No.2 or 3 is selected on the key lock set screen.
•
PV (measured) value is over the scale.
(4) AT is automatically canceled in the following condition during AT execution.
•
Duration equal to or longer than 2 hours passed in the output level of 0% or 100%.
•
Power shutdown.
•
PV (measured) value is over the scale during AT execution.
(5) Starting AT (selecting "
" on the selection screen) during AT execution, no AT is performed and continues running AT execution.
(6) The items enable to be set are as follows:
•
Level setting of the higher limit alarm.
•
Level setting of the lower limit alarm or heater break alarm.
•
Screen number setting on the direct call screen of mode 1 screen group.
(7) Relationship between AT and set value bias is as follows:
•
When SB terminal is shorted before AT execution, AT executes in the condition with SV + set value bias.
•
When SB terminal is opened during AT execution mentioned in the above, AT executes with SV + set value bias condition, then controlled with SV
condition after completing AT execution.
•
When SB terminal is opened, AT executes with SV condition.
•
When SB terminal is shorted during AT execution mentioned in the above, AT executes with SV condition, then controlled with SV + set value bias
condition after completing AT execution.
0-0 basic screen
0-0 AT action
control screen
LED for AT
monitoring
turns on
LED for AT
monitoring
starts flashing
point flashing
point goes off to
indicate registration
key
key
key
Starting
AT action
0-0 basic screen
LED for AT
monitoring
starts flashing
0-1 AT action control screen
LED for AT
monitoring
flashing
LED for AT
monitoring
turns on
LED for AT
monitoring
goes off
point flashing
point goes off to
indicate registration
key
key
key
Aborting
AT action
