NOTE: We are currently working on new PID settings that are determined from the cooling power of a specific piece of equipment. What follows are general guidelines to follow until this process is complete. As soon as new PID values become available a link to them will be added here and on the equipment page (eg. the CCR home page). Contact a member of the sample environment team for more information about this process or PIDs in general. These new PID values take advantage of a feature called a PID zone table. Below you will find a link to a one page manual on how to load a PID zone table.
New PIDs:
- Top Loading CCR (pdf will open in new window)
- CCR-11 (pdf will open in new window)
- CCR-13 (pdf will open in new window)
- CCR-14 (pdf will open in new window)
- CCR-H02 (pdf will open in new window)
- CCR-H03 (pdf will open in new window)
- How to Load a PID Zone Table (pdf will open in new window)
Or for general PID information click here .
Lakeshore 340 or 331 Temperature Controller
|
Coldhead
Model |
Setting |
Temperature Band (upper limit)
|
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Leybold |
P
I D |
400
400 3 |
400
100 1 |
300
75 3 |
250
55 5 |
150
5 5 |
|||||
|
Coldhead
Model |
Setting |
Temperature Band (upper limit)
|
|||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| APD |
P
I D |
500
150 4 |
500
50 3 |
450
50 5 |
400
35 4 |
400
35 3 |
400
30 10 |
400
25 20 |
|||||||
Cryocon Temperature Controller
|
Coldhead
Model |
Setting |
Temperature Band (upper limit)
|
|||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Leybold |
P
I D |
17.9
6.84 0.97 |
51.4
11.2 1.60 |
68.5
18.0 2.57 |
71.3
24.2 3.46 |
75.9
29.4 4.20 |
88.1
31.6 4.51 |
92.3
35.9 5.13 |
104
36.0 5.15 |
100
38.6 5.51 |
109
39.7 5.67 |
108
40.3 5.76 |
|||||||||||
PIDs for "High Temperature" CCR
Note: These systems have long time constants and are notoriously hard to control. We recommend using the
Low and Slow PID
shown below (use throughout the entire temperature range).
High Temperature-CCR
LS340 Controller
P
2
I
1
D
500
Some additional tips:
- Check out the documentation packet posted on the CCR.
- Activate the RAMP function for smoother setpoint changes.
- Add some manual output (the PID loop will add/subtract power as needed). You typically need about 30% power to maintain 300K.
|
High Temperature-CCR
LS340 Controller |
|
|---|---|
| P | 2 |
| I | 1 |
| D | 500 |
General PID Information
Some Definitions:
- T
- The observed temperature
- Tsp
- The set-point or target temperature
- e
- The error signal is a function of Tsp-T
- P
- The proportional gain parameter (labeled "Gain" on some controllers) generates output proportional to e as long as T lies within the "proportional band". Otherwise, the output is either zero or full scale.
- I
-
The integral parameter (or Reset) generates output proportional to the time-integrated error signal. In contrast,
P
acts on the instantaneous error signal
e(t)
.
Without a finite
I
-value, the system tends to stabilize below
Tsp
. For the controllers listed above (except LTC-21) the optimum value of
I
is inversely proportional to the time period (
Tau
) of thermal oscillations in your system ( I=1000/Tau)
For LTC-21 controllers, I is directly proportional to Tau . - D
- The derivative function (or Rate) adresses the problem of overshoot/undershoot of Tsp . D acts on the time-derivative of e(t) and its optimum value is directly proportional to Tau .
Last modified 03-October-2006