Fluke 7381 - Cutout Set-Point

7381
User’s Guide
34
The proportional band should also be wider when fluid viscosity is higher because of the
increased response time.
Easily adjust the proportional band width from the front panel. You can set the width to discrete
values in the selected temperature units. Monitor the stability with a high-resolution thermometer
or with the controller percent output power display to determine the optimum proportional band
width setting. Narrow the proportional band width to the point at which the temperature begins to
oscillate and then increase the band width from this point to 3 or 4 times wider. Table 4 lists
typical proportional band settings for optimum performance with a variety of fluids at selected
temperatures.
Access the proportional band adjustment from the secondary menu. Once in the secondary
menu and you see heater power, push SET to access the proportional band:
Pb=0.101C Proportional band setting
1. Push UP or DOWN to change the proportional band, for example:
DOWN Decrement display
Pb=0.060C New proportional band setting
2. Push SET to accept the new setting and access the cutout set-point. Push EXIT to escape
the secondary menu and ignore any changes made to the proportional band value.
Cutout Set-point
Access the cutout set-point from secondary menu. Once in the secondary menu and you see
heater power, push SET twice to access the cutout set-point. The cutout set-point shows, for
example:
Table 4. Proportional Band - Fluid Table
Fluid Temperature Proportional Band Stability
Water 30.0 °C 0.31 °C
±0.003 °C
Water 60.0 °C 0.31 °C
±0.003 °C
Eth-Gly 50 % 35.0 °C 0.31 °C
±0.005 °C
Eth-Gly 50 % 60.0 °C 0.31 °C
±0.005 °C
Eth-Gly 50 % 100.0 °C 0.4 °C
±0.010 °C
Oil 200.10 35.0 °C 0.6 °C
±0.004 °C
Oil 200.10 60.0 °C 0.6 °C
±0.004 °C
Oil 200.10 100 °C 0.6 °C
±0.004 °C
Oil 710 200 °C 0.4 °C ±0.008 °C