Lakeshore 336, Руководство пользователя

Страница: 78 / 192

66 c
HAPTER
4: Operation
Model 336 Temperature Controller
4.5.1.5.4 Derivative (D)
The derivative parameter (sometimes called rate) is the D part of the PID control
equation. The derivative time constant should normally be somewhere between
p
and
1/i
the integral time in seconds, if used at all. As a convenience to the operator,
the Model 336 derivative time constant is expressed in percent of ¼ the integral
time. The range is between 0% and 200%. Start with settings of 0%, 50%, or 100%,
and determine which setting gives you the type of control you desire. Do not be sur-
prised if the setting you prefer is 0%. Note that by using a percent of integral time,
derivative scales automatically with changes in the integral value and does not have
to be revisited frequently.
To set D, first configure the front panel display to show the desired control loop infor-
mation, then use the
D key on the front panel. A quick way to access the setting if the
control loop information is not already being displayed is to press A , B , C , or D on the
front panel to temporarily display the control loop information while the new setting
is entered. Refer to the section 4.3 for details on configuring the front panel display.
Menu Navigation:
D
Q
(0% to 200%)
Default: 0%
Interface Command:
PID
4.5.1.5.5 Manual Output
Manual Output is a manual setting of the control output. It can function in two differ-
ent ways depending on control mode. In open loop control mode, the Manual Output
is the only output to the load. You can directly set the control output from the front
panel or over the computer interface. In closed loop control mode, Manual Output is
added directly to the output of the PID control equation. In effect, the control equa-
tion operates about the Manual Output setting.
The Manual Output setting is in percent of full scale. Percent of full scale is defined as
percent of full-scale current or power on the selected heater range. Refer to
section 4.5.1.3 to set the Heater Out display. Available full scale current and power
are determined by the heater resistance, Max Current setting, and Heater Range.
Manual Output setting range is 0% to 100% with a resolution of 0.01%.
To set Manual Output, first configure the front panel display to show the desired con-
trol loop information, and then press
Manual Output on the front panel. A quick way
to access the setting if the control loop information is not already being displayed is
to press
A , B , C , or D on the front panel to temporarily display the control loop infor-
mation while the new setting is entered. Refer to section 4.3 for details on configuring
the front panel display.
When an output is configured for Open Loop mode, the Manual Output setting is
available in the Output Setup menu. This is because in the Open Loop mode no Con-
trol Input (feedback sensor) is required, and if none is set then there would be no way
to use the
Manual Output front panel key to set the output unless using the Custom
Display mode. The Control Input parameter can be assigned to a sensor input (that is
not being used for control) as a means of quickly accessing the Manual Output setting
using the
Manual Output front panel key.
Menu Navigation:
Manual Output
Q
(0% to 100%)
Default: 0%
Interface Command:
MOUT