Fluke 7037 User Manual page 47

Figure 8. Bath Temperature Fluctuation at Various Proportional Band Settings
The proportional band should be wider when the higher power setting is used so
that the change in output power per change in temperature remains the same.
The proportional band should also be wider when the fluid viscosity is higher
because of the increased response time.
The proportional band width is easily adjusted from the bath front panel. The
width may be set to discrete values in degrees C or F depending on the selected
units. The optimum proportional band width setting may be determined by
monitoring the stability with a high resolution thermometer or with the controller
percent output power display. Narrow the proportional band width to the point at
which the bath temperature begins to oscillate and then increase the band width
from this point to 3 or 4 times wider. Table 3 lists typical proportional band
settings for optimum performance with a variety of fluids at selected
temperatures.
Fluid
Water
Water
Eth-Gly 50 %
Eth-Gly 50 %
Eth-Gly 50 %
Oil (5cs)
Oil (5cs)
Oil (5cs)
Table 3. Proportional Band- Fluid Table
Temperature
30.0 °C
60.0 °C
35.0 °C
60.0 °C
100.0 °C
35.0 °C
60.0 °C
100 °C
Heater Setting
0.04 °C
Low
Low 0.04 °C
0.05 °C
Low
0.05 °C
Low
0.4 °C
High
Low 0.1 °C
0.2 °C
Low
0.2 °C
Low
Calibration Bath
Controller Operation
figure 8.eps
Proportional Band Stability
±0.001°C
±0.001°C
±0.001°C
±0.001°C
±0.002°C
±0.003°C
±0.002°C
±0.003°C
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