Chapter 6. OPERATION
• Auto-tuning always calculates the excess time and limit sensitivity of thread for two
limit cycles and calculates PID values using characteristics equations, then automati-
cally writes the results.
• The setup data
C21
setting changes the upper and lower output limit used during
auto-tuning.
C21
setting of 1, 3 or 5 causes the lower output limit to be determined by variable
parameter
PA09
and the upper output limit to be determined by
PA10
.
C21
setting of 2 or 4, lower output limit is off and the upper output limit is on.
• The point at which output reverses (lower limit
⇔
upper limit) during auto-tuning is
determined from the SP and PV values at AT startup as follows.
• Auto-tuning performed using a variable parameter
PA08
setting of 3 or 4 causes
auto-tuning to be performed on SP, PID parameters
tP-A1
to
tP-A7
, in order.
• Auto-tuning can be started by the
AT key
, external switch input and by transmission.
The
AT
LED flashes during auto-tuning.
• Auto-tuning terminates without writing PID constants and the
AT
LED goes off
when any of the following conditions occur.
• Operation is terminated by pressing of the
AT key
.
• Operation is terminated by an external switch input.
• Operation is terminated by transmission.
• Mode change occurs. (When the MANUAL mode is invoked; the READY mode
is invoked by setting
PA08
to 1 or 2, the RUN mode is invoked by setting
PA08
to 3 or 4.)
• When PV goes outside the range.
Time
PV
tP-A7
tP-A6
tP-A5
tP-A4
tP-A3
tP-A2
tP-A1
6-13
