Amatrol 990-PC1 User manual

L33354-XA28UEN-E1-S01, REV. A CLOSED-LOOP TUNING
Copyright © 2020 Amatrol, Inc.
S01-1
SKILL 1 TUNE A CONTROL LOOP USING THE AUTO-TUNE METHOD
PROCEDURE OVERVIEW
In this procedure, you will use the controller’s auto-tuning feature to determine the PID values. Then you will
operate the level control loop to observe the response. If the response is not ideal, you will manually tune the PID
values to improve the response.
1. Perform a lockout/tagout.
2. Perform the following substeps to set up the 990-PC1, as shown in figure 1-1.
NOTE
The appearance of the electrical outlet will differ based on the electrical power supplied at your location.
Figure 1-1. 990-PC1 Setup for Closed Loop Level Control
100 120
140
160
180
200
80
60
40
200
0
5
10
15
20
25
30
kPa
psi
100 120
140
160
180
200
80
60
40
200
0
5
10
15
20
25
30
kPa
psi
MANUAL FLOW CONTROL
VALVE FV100 (HFV) OPEN
MANUAL DRAIN VALVE
HV 100C (HV4) CLOSED
MANUAL
DRAIN VALVE
HV 300 (HV3)
CLOSED
CONNECT THE ANALOG
AND DIGITAL CABLES
HAND VALVE HV 100A (HV2)
AND HV 100B (HV1) OPEN
PRESSURE REGULATOR
SET TO 140 kPa (20 psi)

L33354-XA28UEN-E1-S01, REV. A CLOSED-LOOP TUNING
Copyright © 2020 Amatrol, Inc.
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SKILL 1 TUNE A CONTROL LOOP USING THE AUTO-TUNE METHOD
A. Connect the air supply line to the 990-PC1.
B. Set the pressure regulator to 140 kPa (20 psi).
C. Fill the reservoir with water to at least the MIN LEVEL line.
D. Close (fully clockwise) the two process tank manual drain valves, HV 300 (HV3) and HV 100C (HV4).
E. Open (fully counterclockwise) the manual flow control valve, FV 100 (HFV).
F. Open (fully counterclockwise) the flow control hand valves, HV 100B (HV1) and HV 100A (HV2).
H. Connect the circuit shown in figure 1-2.
This circuit allows you to operate a closed loop level control system. Make sure the communication cables are
connected between the two units.
Figure 1-2. Connections for Closed Loop Level Control

L33354-XA28UEN-E1-S01, REV. A CLOSED-LOOP TUNING
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SKILL 1 TUNE A CONTROL LOOP USING THE AUTO-TUNE METHOD
Figure 1-3 shows the wiring diagram for the closed loop level control circuit.
Figure 1-3. Wiring Diagram for a Level Sensor Connected to an Electronic Controller
Figure 1-4 shows the P&ID for the 990-PC1. The active components and wiring are highlighted.
Figure 1-4. 990-PC1 P&ID
24
VDC
+
-
+
-
+-
CONTROLLER INPUTS PRESSURE
SENSOR
+
-
+
-
CONTROLLER
OUTPUT
4-20mA
+
-
I/P
CONVERTER
+
-
DC POWER
SUPPLY
PB1
PB2
AI 1 LT1
A01 FV1
CIRC. PUMP
P1
SV3
ANALOG OUTPUT
CONNECTIONS
SS
S
PI
100-A
HV
100-A
HV
100-B
SV
100-A
FV
100
PI
100-B
FCV
100
LSH
200-B
LSH
200-A
LET
200-A
HV
300
SV
100-B
HV
100-C
SV
100-C
FI
100
FIC
100
IY
100
PC
100
PI
100-C
FE
100
FIT
100
RESERVOIR
TA N K
DUAL-COMPARTMENT
PROCESS TANK
OVERFLOW
LEVEL
SENSOR
PROPORTIONAL
VALVE
CONTROLLER
I/P
CONVERTER
PLANT
AIR
WATER
PUMP

L33354-XA28UEN-E1-S01, REV. A CLOSED-LOOP TUNING
Copyright © 2020 Amatrol, Inc.
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SKILL 1 TUNE A CONTROL LOOP USING THE AUTO-TUNE METHOD
3. Remove the lockout/tagout.
4. Press pushbutton switch PB1 to the off (out) position.
PB1 is used to turn the circulation pump on and off.
5. Perform the following substeps to configure the parameters in the PID controller as a closed loop system.
Typically, most of the parameters will already be configured as needed.
A. Turn on the main circuit breaker to apply power to the system.
B. Press and hold the Pkey for 3 seconds to go to the hidden loop and the configuration loop.
Typically, tunE will appear if additional parameters have not been hidden.
C. Press the Pkey repeatedly until CnFP (configuration loop) displays in the lower display area.
D. With CnFP/no displaying, press the up arrow key to enter the configuration loop.
The first parameter group to display is the input parameters module (1-In).
E. Press the up arrow to go to the 1-In (input menu), if 1-In is not already showing.
F. With 1-In displaying, press the Pkey to enter the input parameters module.
The first parameter, which is input type (tyPE), will display.
G. Under type, use the up or down arrow keys to change the parameter to 4-20 (4-20 mA input).
H. Press the Pkey, which accepts that value and goes to the next parameter.
When a parameter is showing, use the up or down arrow keys to change the value and press the Pkey to
accept that value and move to the next parameter.
I. Continue configuring the input parameters to have the values shown in figure 1-5.
When dual values are shown in the setting column, the first number is in centimeters, and the second number is in
inches. You will use one or the other. If you are not sure which one to use, ask your instructor.
Module 1-Input Parameters (1-In)
Parameter Description Setting (cm/in.)
tyPE Input type 4-20
dCPt Decimal resolution 0.00
FLtr Digital filtering 8
bANd Input filter band .1
SHFt Shift/offset -1.8
dSP1 Display value scaling point 1 (low) 0.00
dSP2 Display value scaling point 2 (high) 70.36/27.70
SPLO Setpoint low limit 1.00/0.50
SPHI Setpoint high limit 6.50/2.50
USr1 User input function 1 SPSL
USr2 User input function 2 ALrS
F1In F key function 1 Trnf
F2In F key function 2 None
Figure 1-5. Input Parameter Values
Notice that the setting for dCPt (decimal resolution) is 0.00, which means two decimal places. This two-decimal
place setting will apply to other parameter settings that take decimal places.
Once the last parameter is entered for that module, the display will return to CnFP.
J. Press the up arrow key until 2-OP (Output Parameters Module) shows.
K. With 2-OP displaying, press the Pkey to enter the output parameters module.

L33354-XA28UEN-E1-S01, REV. A CLOSED-LOOP TUNING
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SKILL 1 TUNE A CONTROL LOOP USING THE AUTO-TUNE METHOD
L. Configure the output parameters to have the values show in figure 1-6.
Module 2-Output Parameters (2-OP)
Parameter Description Setting
OPAC Control action D1A2
CtRL Control mode PID
StPt Setpoint control mode SP
CYC1 OP1 cycle time .5
OP1L Output 1 power lower limit 0
OP1H Output 1 power upper limit 100
Figure 1-6. Output Parameter Values
The setting for the output control action (OPAC) of D1A2 means that output 1 will be direct (output rises when input
rises) acting and output 2 will be the alarm 3 output.
Once the last parameter is entered for that module, the display will return to CnFP.
M. Press the up arrow key until 3-LC (Lockout Parameters Module) shows.
N. With 3-LC displaying, press the Pkey to enter the lockout parameters module.
O. Configure the lockout parameters to have the values show in figure 1-7.
Module 3-Lockout Parameters (3-LC)
Parameter Description Setting
SP Setpoint dISP
OP1 Output power 1 PArA
OP2 Output power 2 HIdE
SPrP Setpoint ramp rate HIdE
PID PID group PArA
r-S Controller status dISP
SPSL Setpoint select PArA
tUnE Auto-tune start HIdE
CtrL Auto control mode HIdE
trnF Control mode transfer HIdE
Figure 1-7. Lockout Parameter Values
A setting of DISP means that parameter can be edited in the main display loop. A setting of PArA means that
parameter can be edited in the parameter loop. A setting of HIdE means that parameter can be edited in the hidden
loop.
Once the last parameter is entered for that module, the display will return to CnFP.
P. Press the Dkey.
The display will flash End in the lower display area for a moment, and the controller will return to the main display
loop.

L33354-XA28UEN-E1-S01, REV. A CLOSED-LOOP TUNING
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SKILL 1 TUNE A CONTROL LOOP USING THE AUTO-TUNE METHOD
6. Perform the following substeps to configure the PID values.
A. Press the Pkey to go to the parameter loop.
B. Press the Pkey 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 Pkey 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 Pkey repeatedly until Intt (integral time value) displays.
G. Press the up or down arrow keys to change the value to 32.
H. Press the Pkey repeatedly until dErt (derivative time value) displays.
I. Press the up or down arrow keys to change the value to 0.
J. Press the Pkey.
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 Dkey 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 Pkey 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.

L33354-XA28UEN-E1-S01, REV. A CLOSED-LOOP TUNING
Copyright © 2020 Amatrol, Inc.
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SKILL 1 TUNE A CONTROL LOOP USING THE AUTO-TUNE METHOD
10. Perform the following substeps to record the reaction of the process.
During the process, you will record the displayed PV value every five seconds until the process reaches steady state.
A. Go into the parameter loop to observe the new PID values and write them down below.
P _______________________________________________________________________________________
I ________________________________________________________________________________________
D _______________________________________________________________________________________
B. If the level is above 3.5 cm or 1.5 in., then drain some water out of the right side of the process tank until the level
is about 3.5 cm or 1.5 in.
C. Open the solenoid drain valve SV 100C (SV3) (PB2 on).
D. Start the circulation pump (PB1 on).
E. Record the value of the PV every five seconds in a table similar to the one in figure 1-9 until the system reaches
steady state.
This data allows you to plot a response curve for the process. If the controller is properly tuned, the response curve
should indicate quarter wave decay. Remember that it is acceptable for the amplitude of the second oscillation to
be smaller than one quarter the amplitude of the first occillation.
PROPORTIONAL-INTEGRAL-DERIVATIVE CONTROL RESPONSE
TIME
(seconds)
PV
READING
TIME
(seconds)
PV
READING
TIME
(seconds)
PV
READING
TIME
(seconds)
PV
READING
0 75 150 225
5 80 155 230
10 85 160 235
15 90 165 240
20 95 170 245
25 100 175 250
30 105 180 255
35 110 185 260
40 115 190 265
45 120 195 270
50 125 200 275
55 130 205 280
60 135 210 285
65 140 215 290
70 145 220 295
Figure 1-8. Table to Record Response

L33354-XA28UEN-E1-S01, REV. A CLOSED-LOOP TUNING
Copyright © 2020 Amatrol, Inc.
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SKILL 1 TUNE A CONTROL LOOP USING THE AUTO-TUNE METHOD
F. Create a graph of PV vs. time, similar to figure 1-10 for PV in inches or figure 1-11 for PV in cm, on a piece of graph
paper.
You will use this to plot the response of the system.
Figure 1-9. Graph of PV (inches) vs. Time
Figure 1-10. Graph of PV (cm) vs. Time
2.3
2.2
2.1
2.0
1.9
1.8
1.7
1.5
1.6
1.4
1.3
1.2
1.1
1.0
0708090 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290300605040302010
TIME
(SECONDS)
PV
(INCHES)
0708090 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290300605040302010
PV
(cm)
TIME
(SECONDS)
4.75
5.0
4.25
4.5
3.75
4.0
3.5
5.5
5.75
5.25

L33354-XA28UEN-E1-S01, REV. A CLOSED-LOOP TUNING
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SKILL 1 TUNE A CONTROL LOOP USING THE AUTO-TUNE METHOD
G. Plot the response using the data you collected in substep D.
Your response curve should be similar to the ones in figure 1-12 for PV in inches or figure 1-13 for PV in cm.
The initial value for your response curve will vary depending on how much the level dropped while you were
calculating the new tuning parameters.Your response may have little overshoot, which is good also.
Figure 1-11. Response of the System (PV in inches)
Figure 1-12. Response of the System (PV in cm)
2.3
2.2
2.1
2.0
1.9
1.8
1.7
1.5
1.6
1.4
1.3
1.2
1.1
1.0
0708090 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290300605040302010
PV
(INCHES)
TIME
(SECONDS)
SP
0708090 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290300605040302010
PV
(cm)
TIME
(SECONDS)
SP
4.75
5.0
4.25
4.5
3.75
4.0
3.5
5.5
5.75
5.25

L33354-XA28UEN-E1-S01, REV. A CLOSED-LOOP TUNING
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SKILL 1 TUNE A CONTROL LOOP USING THE AUTO-TUNE METHOD
11. Perform the following substeps to evaluate the response using the auto-tuned PID values.
NOTE
For a process in a plant or factory, before you adjust PID values, verify that no mechanical issues are causing the
less than desirable results. For example, if the controller increases its output steadily, but the PV does not respond
for a while, but then makes a large jump, you should suspect a valve that is sticking and releasing. Also, if the
controller output for a steady state is above 90% or below 10%, then suspect the valve is not sized correctly. No
amount of PID fine tuning will correct these mechanical issues.
A. Determine the desired outcome for this process.
This sounds too obvious, but it is important. Is speed the most important or is stability the most important? Does
the process need to arrive at SP as quickly as possible and overshoot with diminishing oscillations is acceptable?
Does the process need to operate at a stable PV during variable conditions and oscillations are undesirable? Your
instructor may decide to make up arbitrary conditions for you.
B. Determine if the process is currently too fast and too unstable.
If you determine it is too unstable, the proper correction depends on the cause of the instability.
•If the proportional band is set too low, try doubling the present value.
•If the integral time is set too short, try multiplying the time by two or three.
•If the derivative is set too low, then increase it or eliminate it by setting it to zero. Derivative is not really needed
in a level process. A derivative that is set way too long can cause oscillations.
C. Determine if the process is currently too slow and sluggish.
If you determine it is too sluggish, the proper correction depends on the cause of the sluggishness.
•If the proportional band is set too wide, try cutting in half the present value.
•If the integral time is set too long, try decreasing the time. If you go too short a time, it will cause oscillations.
•If the derivative is set too high, then decrease it or eliminate it by setting it to zero.
D. Write down your proposed new PID values to try below.
It may be that the auto-tuned values gave acceptable results. If so, you would be done. However, you might
try some slightly different values to see if you can improve the response a little. Be prepared to explain to your
instructor why you think your new values may be better.
P _______________________________________________________________________________________
I ________________________________________________________________________________________
D _______________________________________________________________________________________
E. Repeat step 10 and record the results on a new graph.
Determine if the new values produced a better response than the auto-tuned values. For a process in a plant, you
may need several adjustments over a period of days before you reach the ideal PID values.
12. Perform the following substeps to shut down the 990-PC1.
A. Place PB1 in the OFF position (out).
This stops the circulation pump.
B. Place PB2 in the OFF position (out).
This closes the solenoid drain valve SV 100C (SV3).
C. Open (fully counterclockwise) the process tank’s right manual drain valve, HV 100C (HV4), to drain the right side
of the tank. Leave the left drain valve, HV 300 (HV3), closed. When the right side of the tank is empty, close (fully
clockwise), the right drain valve.
The water should remain in the left side of the process tank.
D. Turn off the main circuit breaker.
E. Disconnect the control circuit.