Extech Instruments 48VTR User Manual page 16

Second Programming Menu Level
Press and hold the SCROLL and RETURN keys simultaneously to enter this level from
the first programming level. To return to normal operation at any time, press the
RETURN key.
NOTE: This is the Manual Tuning programming level. Rather than attempting to manually tune the
controller, it is strongly recommended that AUTO TUNING be employed. Auto Tuning automatically sets
the tuning parameters. Refer to the Auto Tuning Section for instructions. Improper use of the tuning
parameters can cause severe process disturbances. Only personnel familiar with manual tuning should
attempt to adjust the parameters in the second menu level. Manual tuning is beyond the scope of this
user guide.
Pb Proportional Band. Setting range from 0.0 to 100.0% of controller's Span. The
controller's span equals the HiLt (high limit) minus the LoLt (low limit). High and
Low Limit parameters can be found in the 3
Default = 10.0%. Set Pb to 0.0% for ON/OFF control action. This value is
automatically calculated by activating the AUTO TUNE function
ti Integral (Reset). 0 to 3000 seconds setting range. Default = 240. This value is
automatically calculated by activating the AUTO TUNE function.
td Derivative (Rate). 0 to 3000 seconds setting range. Default = 40. This value is
automatically calculated by activating the AUTO TUNE function.
rd
Menu Level.
16 Model 48VTR - Version 5.0 – January 2006