Rotate the
Display Select Switch
to
TE I
(
Shift Button
OFF)
to monitor
the current fl owing through the thermoelectric. Rotate the
Display Select
Switch
to
TE V
(
Shift Button
OFF)
to monitor the voltage across the
thermoelectric.
Begin Autotune Optimization
6
Autotune:
Rotate the
Display Select Switch
to
P
and toggle the
Shift
Button
ON
. Use the
Digi-Pot Adjust Knob
to change the value. To begin
Autotune optimization, adjust the P value to display AutS or Autd.
AutS: Setpoint Response Autotune Optimization
Autd: Disturbance Rejection Autotune Optimization
You determine what kind of control loop the Autotune will use based on
your settings for the I and D terms. If set to zero, that control term
will not be used. The following chart shows which control modes are
available and the appropriate I and D settings. Rotate the
Display
Select Switch
to
I
then
D
, making any necessary adjustments with the
Digi-Pot Adjust Knob
.
For this example, adjust
P
to AutS,
I
to 1.0, and
D
to 1.0 .
Manual setting:
Adjust P to a value other than AutS or Autd.
Enable the Output Current
Press the
Output Button
to enable the output current and begin the
Autotune optimization sequence. The
ON LED
indicator will fl ash while
Autotune optimization is in progress. Once the Autotune sequence is
fi nished, the LFI-3751 will control to the desired operating temperature
entered in Step 5. Refer to Chapter 2, Autotune PID operation for
more detail.
Measure Actual Temperature
8
Rotate the
Display Select Switch
to
ACT T
(
Shift Button
OFF)
to
monitor the load temperature.
ACT T
temperature now approaches
the
SET T
temperature.
Measure Thermoelectric Current and Voltage
9
Chapter 1 - Quick Start
Nine Steps to Operating the LFI-3751
P
ACT T
LIM I
AUX T
TE V
SET T
TE I
B
C
I
A
D
ON
OUTPUT
19
1
P
ACT T
LIM I
AUX T
TE V
SET T
TE I
B
C
I
A
D
°
C
7
P
ACT T
LIM I
AUX T
TE V
SET T
TE I
B
C
I
A
D
AMPS
VOLTS
or
Control Mode:
PID
PI
PD
P
I
non-zero
non-zero
OFF = zero
OFF = zero
D
non-zero
OFF = zero
non-zero
OFF = zero
Summary of Contents for LFI-3751
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Page 13: ...1 Chapter 1 Quick Start 13 1 ...
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Page 21: ...2 Chapter 2 Front Panel Operation 21 2 ...
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Page 69: ...3 Chapter 3 Rear Panel Operation 69 3 ...
Page 75: ...3 4 Chapter 4 Remote Interface Reference 75 4 ...
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Page 127: ...5 Chapter 5 Specifications 127 5 ...
Page 131: ...Appendix CAT 220 Cable Accessory Diagram 131 ...
