Newport LDC-3706 Series, Руководство пользователя

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December 2019 22 LDC-3706 Series Laser Controller
Manual: In MANUAL mode the user can adjust the PID values or view the preset PID values
that were last loaded (note: if the user adjusts the preset PID values in manual PID mode, the
change will not permanently affect the preset PID value). To manually adjust the PID values
first select the MANUAL LED by pressing MODE, then press SELECT (left) to change
between P, I, and D. To adjust the PID value, press SET (left); to move to the next value
press SELECT (left).
To load a preset PID value use the MODE button to cycle to the MANUAL LED, and then
press the SELECT (left) button, then using the SELECT (left) or ADJUST knob, display the
Adjust Preset menu. Press the SET (left) button and cycle through the presets until the
correct preset is displayed then press the SET button to load the values. Use the SELECT
(left) button to view the loaded preset P, I, and D values.
Auto-tune – The auto-tune mode will calculate a thermal system's PID coefficients
through an iterative PID temperature control process. To enter the auto-tune mode first
press MODE until the AUTO LED is illuminated, and then SELECT to ready the
instrument for the auto-tune process. The screen will say “”Start Autotune <SET>”. While
this is displayed, press SET to begin the auto-tune procedure. When the LDC-3706
successfully completes the auto-tune the instrument will revert back to MANUAL PID
mode and the calculated PID values will overwrite the current PID values in MANUAL
mode. If the auto-tune process fails an error will be displayed on the screen. For more
information on the auto-tune process see Appendix B. There are limitations to the auto-
tune feature. Any of the following will cause the
auto-tune algorithm to fail:

Thermal systems requiring the proportional term to be less than 0.5

Noisy temperature measurements

Reaching any output off enable condition (such as temperature or voltage limits) during
the auto-tune operation.
If the auto-tune algorithm fails for a particular thermal system, it may be necessary to
modify the PID coefficients manually.