Rockwell Automation 1746-BTM Barrel Temperature Control Module User Manual - Manual (Page 78)

Publication 1746-UM010B-EN-P - April 2001
9-10 Sample Program
The autotune abort bit O:1.12/2 must be turned off after an autotune
is aborted, if not the next time you try to enable an autotune it will
immediately be aborted. When you set bit O:1.12/2 high you must
also check that the autotune in progress bit I:1.8/11 is low. When that
happens reset the autotune abort bit O:1.12/2.
Figure 9.6 Correct way to abort an Autotune
TIP
•
Do not set the Autotuning enabled bits in the
output image table in the same scan that you set
the invoke autotune bit.
•
Do not perform M1 or M0 file transfers without
using the up/download request bits (output word
12 bits 12 thru 15) and the up/download request
ready bits (input word 9 bits 12 thru 15). These
bits must be used to insure block integrity.
•
When you need to disable a loop of control do
not just put a contact in front of the output TPO
bit. This will cause the PID loop to windup,
because the loop is still active and wants to
control. When you re-enable the loop, it will
oscillate about the setpoint then come into
control. The correct way to shut down a loop is
to put the loop into manual mode with 0% CV
output.