Rockwell Automation 1746-BTM Barrel Temperature Control Module User Manual - Manual (Page 58)

Publication 1746-UM010B-EN-P - April 2001
5-12 Control and Autotune a Loop
A synopsis of the complete tuning procedure would be as follows:
1. Wait for all zones to be stable. A module wide event inclusive of
all zones enabled for control and autotune at the time of auto
tune invoke.
2. When stability has been qualified, all enabled zones will be
subject to maximum configured output. At this time the system
is observed for a departure from stability to quantify the
deadtime of the system.
3. The output continues at the same value until a maximum rate of
change for each active zone in the auto tune has been identified
and recorded.
4. For heat or cool only zones, the test is now complete, auto tune
finishes, and the individual zones revert to their current
configuration and mode.
5. For zones designated as heat/cool, they will continue to setpoint
under ‘slow’ closed loop control and stabilize. Again, this
stabilization is a module wide event and is inclusive of all heat/
cool zones engaged in the current auto tune.
6. When stability has been qualified, all enabled zones will be
subject to maximum (cool) configured output. At this time the
system is observed for a departure from stability to quantify the
deadtime of the system.
7. The output continues at the same value until a maximum rate of
change for each zone still active in the auto tune has been
identified and recorded.
8. The test is now complete, auto tune finishes, and the individual
zones revert to their current configuration and mode.
If for any reason the auto tune does not successfully complete for any
individual zone, that zones auto tune and gain parameters will not be
updated, and error codes will be displayed. Refer to Locating Error
Code Information on page 8-2