Microstat He Manual
6.4
Temperature control above 4.2K
You can control the temperature of the heat exchanger between 4.2K and 500K. The Helium flow and heater power have to be adjusted
in order to reach the desired set point.
The MercuryiTC can control the heater power automatically, adjusting the applied power to maintain the set temperature. The Mercury
iTC is a three-term controller - the temperature control is optimised by setting the best values for:
• Proportional band (P)
• Integral action time (I)
• Derivative action time (D)
On the MercuryiTC home screen (see above), tap
Control
to give the following screen:
Figure 6.2: Mercury control screen
Tap
PID Table
to display a screen similar to the following:
This screen shows that a standard PID table, in this case, “Microstat He Mercury.pid”, is already loaded into the iTC.
Tap
Load
to view alternative PID tables. These may be from the factory or created by the user.
Tap a filename to select it and then tap
Load
to load the selected PID table.
The PID values given in the test results for the system are suitable to give good stability. If you wish to improve the stability further you may
be able to do this by adjusting the three terms slightly. In Manual mode, individual PID values can be changed during operation. Control
theory and the procedure for optimising the PID values are described in the mercury iTC manual.
Tap
Close
to return to the control screen, then tap
Home
to return to the home screen.
© 2017 Oxford Instruments Nanoscience
MAN-MHE-1.1.0 (28ff3d8) Sep 2017
22
