Auto/Manual Mode Changeover; Auto Mode And Manual Mode - Mitsubishi Electric MELSEC FX Series User Manual

FX -4LC User's Manual
3U
6.10

AUTO/MANUAL mode changeover

6.10.1 AUTO mode and MANUAL mode

The mode can be changed over between "AUTO mode" and "MANUAL mode".
The AUTO mode is selected when "K0" is written to the AUTO/MANUAL mode changeover buffer memory.
The MANUAL mode is selected when "K1" is written to the AUTO/MANUAL mode changeover buffer
memory.
Set the control mode to 0 to 3 (PID control) for performing manual mode.
In the MANUAL mode, b13 of the event becomes "1" to notify the MANUAL mode.
0.25 sec is required to change over the mode.
During changeover, the balance-less, bump-less function is actuated.
• AUTO mode
In the AUTO mode, the measured value (PV) or external input value is compared with the set value (SV),
and the control output (MV) is given by PID arithmetic operation.
The AUTO mode is selected at shipment.
In the AUTO mode, the MANUAL output set value is always set to the control output value (MV).
• MANUAL mode
By changing the MANUAL output set value, the output value can be fixed to an arbitrary value.
The actual output value is within the range from the output limiter lower limit to the output limiter upper limit.
The output change ratio limiter setting is valid.
The MANUAL output set value can be changed while b13 of the event is ON.
Associated buffer memory
BFM No.
CH1 CH2 CH3 CH4
#1 #2 #3
#25 #26 #27
#54 #94 #134 #174 AUTO/MANUAL mode changeover
#55 #95 #135 #175 MANUAL output set value
#64 #104 #144 #184 Output limiter upper limit/Heating upper output limiter setting
#65 #105 #145 #185 Output limiter lower limit
#67 #107 #147 #187 Output change ratio limiter
Caution
• The MANUAL mode is not available while heating/cooling PID control is being performed.
• Even in MANUAL mode, the temperature alarm function is functional.
58
→ For details on the balance-less, bump-less function, refer to Subsection 6.10.2.
#4 Event (b13 MANUAL mode transition completed flag)
#28 External input value
→ For details on the control mode switch, refer to Section 6.2.
Description
6 Introduction of Functions
6.10 AUTO/MANUAL mode changeover
Reference
Subsection 8.2.2
Subsection 8.2.8
Subsection 8.2.18
Subsection 8.2.19
Subsection 8.2.28
Subsection 8.2.29
Subsection 8.2.31