Lake Shore Model 340 Temperature Controller User’s Manual
2-14
Cooling System Design
2.9 ZONE
TUNING
Once the PID tuning parameters have been chosen for a given setpoint the whole process may have to be
done again for other setpoints significantly far away that have different tuning needs. Trying to remember
when to use which set of tuning parameters can be frustrating. The Model 340 has a Zone feature as one of
its tuning modes that can help.
To use the Zone feature the user must determine the best tuning parameters for each part of the temperature
range of interest. These parameters are then entered into the Model 340 where up to ten zones can be
defined with different P, I, D, heater range and manual output. A setpoint setting is assigned as the maximum
temperature for that zone. The minimum temperature for a zone is the setpoint for the previous zone, 0 K is
the starting point for the first zone. When the zone tuning mode is on, appropriate control parameters are
chosen automatically, each time the setpoint is changed to a new temperature zone.
Control parameters can be determined manually or by using the AutoTune feature. AutoTune is a good way
to determined a set of tuning parameters for the control system that can then be entered as zones. Once the
parameters are chosen, AutoTune is turned off and zone tuning takes over.