Mitsubishi Electric MELSEC FX Series User Manual page 56

FX -4LC User's Manual
3U
Associated buffer memory
BFM No.
CH1 CH2 CH3 CH4
#0
#1 #2 #3
#5 #6 #7
#48 #88 #128 #168 Set value (SV)
#56 #96 #136 #176 AT (auto tuning) execution command
#58 #98 #138 #178 Proportional band (P)/Heating proportional band (P)
#59 #99 #139 #179 Cooling proportional band (P)
#60 #100 #140 #180 Integral time (I)
#61 #101 #141 #181 Derivative time (D)
#64 #104 #144 #184 Output limiter upper limit/Heating upper output limiter
#65 #105 #145 #185 Output limiter lower limit
#67 #107 #147 #187 Output change ratio limiter
#73 #113 #153 #193 Setting change ratio limiter
#74 #114 #154 #194 AT (auto tuning) bias
#78 #118 #158 #198 Loop breaking alarm judgement time
#254
Caution
• While the setting change ratio limiter is operating, auto tuning is started when the set value (SV) reaches
the auto tuning point.
• If control is started while both the AT execution command buffer memory and ST execution command
buffer memory are set to "1", auto tuning is performed.
• If the AT execution command buffer memory is set to "1" while startup tuning is being performed, startup
tuning is aborted and auto tuning is started.
• If auto tuning is performed while the output change ratio limiter is set to any value other than "0", optimal
PID constants may not be acquired.
Do not use the output change ratio limiter when performing auto tuning.
• The loop breaking alarm function is disabled while auto tuning is being performed.
50
Flag (b4 to b7 AT/ST abnormal end flag)
#4 Event (b14 AT (auto tuning) being performed)
#8 Measured value (PV)
Set value backup command
Description
6 Introduction of Functions
6.8 Auto Tuning Function
Reference
Subsection 8.2.1
Subsection 8.2.2
Subsection 8.2.3
Subsection 8.2.15
Subsection 8.2.20
Subsection 8.2.22
Subsection 8.2.23
Subsection 8.2.24
Subsection 8.2.25
Subsection 8.2.28
Subsection 8.2.29
Subsection 8.2.31
Subsection 8.2.37
Subsection 8.2.38
Subsection 8.2.42
Subsection 8.2.70