Chapter 3: Use
22
This process should take less than one minute. At the end of the transfer process, a second dialog box, similar to
Figure 3-2, appears.
Figure 3-2. Final Dialog Box Displayed by a TDC5 Script
Click the
OK
button to end the reset process.
Automatic versus Manual Tuning
Tune your TDC5 automatically whenever possible.
Unfortunately, the system response with many electrochemical cells is too slow for auto tuning. You cannot
auto tune if a 5
C increase or decrease in the system temperature takes more than ten minutes. In most cases,
auto tune on an electrochemical cell will fail unless the system is actively cooled.
A full description of the manual tuning of PID controllers is beyond the scope of this manual. However, a later
section of this chapter does give a relatively simple step-by-step procedure for manually tuning the TDC5.
The following table contains the tuning parameters for a Gamry Instruments Flex Cell used with a 300 W
heating mantle and switched cooling using water flow though the standard cooling coil. The solution was stirred.
Auto Tuning the TDC5
We strongly recommend that you auto-tune the TDC5 as explained in the
Omega
®
User
’
s Guide
, section 4.6.2.
Parameter (Symbol)
Setting
Proportional Band 1
9
C
Reset 1
685 s
Rate 1
109 s
Cycle Time 1
1 s
Dead Band (db)
14