L33354-XA28UEN-E1-S01, REV. A CLOSED-LOOP TUNING
Copyright © 2020 Amatrol, Inc.
S01-6
SKILL 1 TUNE A CONTROL LOOP USING THE AUTO-TUNE METHOD
6. Perform the following substeps to configure the PID values.
A. Press the
P
key to go to the parameter loop.
B. Press the
P
key repeatedly until
PId
displays.
C. Press the up
or down
arrow keys to change the value to
1
(group 1).
NOTE
In this procedure, you are only configuring one profile, which is profile 1. However, a process in a plant may require
several steps. For example, the first step may need the level to ramp up from 1 m to 8 m in 10 minutes. Then it
needs to soak at 8 m for 20 minutes. Then the level needs to ramp down to 1 m in 10 minutes. Finally, it needs to
soak at 1 m for 30 minutes. Many PID controllers allow you to use a different PID profile for each step and program
each profile separately.
D. Press the
P
key repeatedly until
ProP
(proportional band value) displays.
E. Press the up
or down
arrow keys to change the value to
1.5
.
F. Press the
P
key repeatedly until
Intt
(integral time value) displays.
G. Press the up
or down
arrow keys to change the value to
32
.
H. Press the
P
key repeatedly until
dErt
(derivative time value) displays.
I. Press the up
or down
arrow keys to change the value to
0
.
J. Press the
P
key.
7. Perform the following substeps to verify the correct zero level is displaying.
A. Open manual drain valve
HV 100C
(
HV4
), which is the drain valve on the right.
B. Turn on
PB1
to run the pump for about 15 seconds and then turn
PB1
off.
C. Close
HV 100C
(
HV4
).
D. If the PV value on the display is not approximately 0.00, then adjust the value in the display shift/offset (SHFt)
parameter, which is in the input parameters module (1-In).
E. If not in the display loop, press the
D
key to show the main display.
The setpoint value will show in the lower line on the display.
F. Use the up
and down
arrow keys to adjust the setpoint value to
3.5
(if using centimeters) or
1.5
(if using
inches).
8. Perform the following steps to adjust the water level in the process tank so that it will not adversely affect the response
plots in this skill.
A. Start the circulation pump by pressing
PB1
to the
ON
position.
B. Monitor the water level in the process tank. When it reaches approximately 3.5 cm (1.5 in.) in both the left and right
sides of the tank, press
PB1
to the
OFF
position to turn off the circulation pump.
C. Press PB2 to the
OFF
position.
The water should remain in both sides of the process tank.
D. Adjust the setpoint to
5.0
cm (
2.0
in.).
9. Perform the following substeps to auto-tune the PID controller.
A. Press and hold the
P
key to enter the hidden loop.
B. Insure that auto control mode (
CtrL
) is set to
PID
.
C. Insure that control mode transfer (
trnF
) is set to
Auto
.
D. Turn on PB1 and PB2 to start the pump and turn on the solenoid valve.
E. Change the auto-tune start (
tUnE
) setting to
YES
.
You may need to re-enter the hidden loop to find tUne. This starts the auto-tuning process, which may take a few
minutes. During this time AT will flash on and off on the left side of the display. The AT will stop flashing when the
auto-tuning is complete. If the auto-tuning takes way too long, you may stop it by changing the value of tUne from
YES to nO. It should finish auto-tuning within four minutes.
