Mitsubishi Electric NZ2GF2B-60TCTT4 User Manual page 357

(57)CH AT bias setting (address: 2A1H, 2A3H, 2A5H, 2A7H)
The point set as the set value (SV) in the auto tuning can be rearranged by using this remote buffer memory area.
The auto tuning function determines each PID constant by performing the two-position control toward the set
value (SV) and making a temperature process value (PV) hunting.
Set CH AT bias setting (address: 2A1H, 2A3H, 2A5H, 2A7H) when an overshoot caused by the hunting is
improper.
The auto tuning is performed with having the AT point (the point rearranged by the setting) as its center. When
the auto tuning is completed, AT bias is not added and a control is performed toward the set value (SV).
For details on the auto tuning function, refer to the following.
Page 159, Section 8.3.7
When AT bias is set to minus value (reverse action)
Ex.
Temperature process value (PV)
Set value (SV)
AT point
(a) Setting range
The setting range is from (-(full scale)) to full scale. The setting range depends on the input range setting.
(Page 312, Appendix 3 (5))
When remote buffer memory values are set as following, the setting range is -6000 to 6000.
Ex.
• CH Input range (address: 100H, 130H, 160H, 190H): 38 (temperature measurement range -200.0 to
400.0, resolution: 0.1)
(b) Setting unit
The value to be set differs depending on the stored value in CH Decimal point position (address: 620H,
621H, 622H, 623H). (Page 362, Appendix 3 (68))
• No decimal place (0): Set a value in 1 ( or digit) unit.
• One decimal place (1): Set a value in 0.1 () unit (tenfold value).
(c) Enabling the setting
Enable the setting contents by either of the following.
• Turning off and on Initial data setting request flag (RY9) while the operations of all channels are stopped
• Turning off and on During operation setting change instruction (RY10)
(d) Default value
The default values are set to 0 in all channels.
(e) Precautions
For CH AT bias setting (address: 2A1H, 2A3H, 2A5H, 2A7H), set the range where PID operation fluctuates
slightly and the control result get no effect.
Depending on the controlled object, accurate PID constants may not be obtained.
Standard Heating-cooling
CH□ AT bias setting
(address: 2A1H, 2A3H, 2A5H, 2A7H)
Time
APPENDICES
A
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