ThermoWorks 9150-X HART SCIENTIFIC 9150 THERMOCOUPLE FURNACE - Manual (Page 31)

troller cannot respond very well to changing conditions or noise in the system.
If the proportional band is too narrow the temperature may swing back and
forth because the controller overreacts to temperature variations. For best con-
trol stability the proportional band must be set for the optimum width.
The proportional band width is set at the factory to about 30.0°C. The propor-
tional band width may be altered by the user if he desires to optimize the con-
trol characteristics for a particular application.
The proportional band width is easily adjusted from the front panel. The width
may be set to discrete values in degrees C or F depending on the selected units.
The proportional band adjustment can be accessed within the secondary menu.
Press “SET” and “EXIT” to enter the secondary menu and show the heater
power. Then press “SET” twice to access the proportional band.
S+E
Access heater power in secondary menu
100.0 P Heater power in percent
S
Access set-point voltage
11.934 U Set-point voltage in millivolts
S
Access proportional band
ProP Flashes and then displays the setting
30.0 Proportional band
To change the proportional band, press “UP” or “DOWN.”
30.5 New proportional band setting
To store the new setting press “SET”. Press “EXIT” to continue without storing
the new value.
S
Accept the new proportional band setting
8.9 Controller Configuration
The controller has a number of configuration and operating options and calibra-
tion parameters which are programmable via the front panel. These are ac-
cessed from the secondary menu after the proportional band function by
pressing “SET”. Pressing “SET” again enters the first of three groups of config-
uration parameters—operating parameters, serial interface parameters and cali-
9150 Portable Furnace
User’s Guide
30