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(e) Calculated values of PID constants after auto tuning
If a calculated value of PID constants after auto tuning exceeds one of the following ranges, auto tuning ends in
fail.
•CH Proportional band (P) setting (Un\G35, Un\G67, Un\G99, Un\G131): 1 to 10000 (0.1% to 1000.0%)
•CH Integral time (I) setting (Un\G36, Un\G68, Un\G100, Un\G132): 1 to 3600 (1s to 3600s)
•CH Derivative time (D) setting (Un\G37, Un\G69, Un\G101, Un\G133): 0 to 3600 (0s to 3600s)
If auto tuning ends in fail due to the calculated value of PID constants as described above, the system configuration needs to
be reconsidered (such as selecting proper heater capacity).
(f) Change of the upper limit setting limiter or lower limit setting limiter and the set
value (SV)
If the set value (SV) goes out of the setting range due to the change in one of the following buffer memory
areas, auto tuning ends in fail.
•CH Upper limit setting limiter (Un\G55, Un\G87, Un\G119, Un\G151)
•CH Lower limit setting limiter (Un\G56, Un\G88, Un\G120, Un\G152)
(g) Other conditions
In addition to the conditions described up until here, if any of the following conditions applies, auto tuning ends
in fail.
•CH PID control forced stop instruction (YnC to YnF) has been turned on from off. ( Page 58,
Section 3.3.3 (7))
• Hardware failure has occurred.
• In standard control, CH Proportional band (P) setting (Un\G35, Un\G67, Un\G99, Un\G131) has been
set to 0. (has been set to two-position control) ( Page 105, Section 3.4.2 (15))
• In heating-cooling control, CH Heating proportional band (Ph) setting (Un\G35, Un\G67, Un\G99,
Un\G131) has been set to 0. (has been set to two-position control) ( Page 105, Section 3.4.2 (15))
(8) Operation on completion of auto tuning
(a) Normal completion
The Q64TCN operates as follows.
• Turns off CH Auto tuning status (Xn4 to Xn7)
• Stores the PID constants in the buffer memory ( Page 177, Section 4.6 (3))
• Stores a value in CH Loop disconnection detection judgment time (Un\G59, Un\G91, Un\G123,
Un\G155) (If this was set to 0 (s) at the start of auto tuning, the setting remains unchanged.)
(b) Abnormal completion
The Q64TCN operates as follows.
• Turns off CH Auto tuning status (Xn4 to Xn7).
• Does not store the PID constants in the buffer memory. ( Page 177, Section 4.6 (3))
(9) Checking the completion of auto tuning
The completion of auto tuning can be checked by the status change from on to off in CH Auto tuning status
(Xn4 to Xn7).