Rockwell Automation 1746-BTM Barrel Temperature Control Module User Manual - Manual (Page 49)

Publication 1746-UM010B-EN-P - April 2001
Control and Autotune a Loop 5-3
•
Set the TPO period smaller than the system dead time. Autotune
algorithm may calculate excessive gains if system dead time is
less than the TPO period. This may cause the PV to overshoot
Figure 5.2 Set TPO Period
•
The autotune algorithm does not take the temperature to
setpoint. When autotune is complete, the zones will return to
the mode (auto or manual) that was selected before autotune.
Figure 5.3 Autotune setpoint zones
Temperature
Output (CV)
system dead time
1 TPO period
System dead time should be larger than one
TPO period for autotune to work properly
Time t
0
output (CV)
changed
Temperature
system dead
time
maximum slope
Return to the control mode
that was selected before
autotune
autotune
complete
Time