Proportional (P); Integral (I) - Lakeshore 335 User Manual

60 c 4: Operation
HAPTER
Model 335 Temperature Controller
In the Monitor Out mode, the Control Input parameter is used to determine the
source of the output voltage. In the Open Loop mode, the Control Input parameter
can be set simply for convenience in order to easily access the associated output's
Manual Output and Heater Range parameters using the Direct Operation keys. Refer
to section 4.2.1.1 for details on Direct Operation keys.
Menu Navigation:
Output SetupQOutput (1 or 2)Q
Default:
Output 1QControl InputQ(Input A)
Output 2QControl InputQ(Input B)
Interface Command: OUTMODE

4.5.1.7.2 Proportional (P)

The proportional parameter (also called gain) is the P part of the PID control equation.
It has a range of 0 to 1000 with a resolution of 0.1. The default value is 50. Enter a
value greater than 0 for P when using closed loop control.
To set P, first configure the front panel display to show the desired control loop infor-
mation, then use the P key on the front panel. A quick way to access the setting if the
control loop information is not already being displayed, is to use the front panel A or B
keys to temporarily display the control loop information while the new setting is
entered. Refer to section 4.3 for details on configuring the front panel display.
Menu Navigation:
PQ(0 to 1000)
Default: 50
Interface Command: PID

4.5.1.7.3 Integral (I)

The integral parameter (also called reset) is the I part of the PID control equation. It
has a range of 0 to 1000 with a resolution of 0.1. The default value is 20. Setting I to 0
turns the reset function off. The I setting is related to seconds by:
I =1000/I
setting seconds
For example, a reset number setting of 20 corresponds to a time constant of 50 s. A
system will normally take several time constants to settle into the setpoint. The 50 s
time constant, if correct for the system being controlled, would result in a system that
stabilizes at a new setpoint in between 5 min and 10 min.
To set I, first configure the front panel display to show the desired control loop infor-
mation, then use the I key on the front panel. A quick way to access the setting if the
control loop information is not already being displayed is to use the front panel A or B
keys to temporarily display the control loop information while the new setting is
entered. Refer to section 4.3 for details on configuring the front panel display.
Menu Navigation:
IQ(0 to 1000)
Default: 20
Interface Command: PID
QControl Input (None, Input A, Input B)
ENTER