Tracking Function - Mitsubishi Electric MELSEC-Q Series User Manual

3 SPECIFICATIONS
3.2.15 SV tracking function
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(1) SV tracking function
When control is switched, drastic change of the set value (SV) is prevented.
In case of the following control shifts, this function is executed.
• Switching from the program control mode (RUN) to the normal control mode,
manual control mode 1, or manual control mode 2
• Switching cascade control from ON to OFF while it is executed in the normal
control mode
Depending on the condition in which control was switched, the set value (SV)
may change drastically, causing the manipulated value (MV) to do so as well.
Processing the set value (SV) as described below, the Q62HLC prevents
system instability caused by drastic change of the manipulated value (MV).
Control shift
Before
Program control mode
(RUN)
Cascade control ON
(normal control mode)
(Example) When the mode is switched from the program control mode to the
normal control mode
When the SV tracking function is used, the value right before the mode shift is
stored as the set value (SV) after the mode is switched from the program
control mode to the normal control mode.
This processing prevents drastic change of the set value (SV) and maintains
stable control.
After checking the stored set value (SV), change it to the one to be controlled,
then start the control.
After
• Normal control mode
• Manual control mode 1
• Manual control mode 2
Cascade control OFF
(normal control mode)
MELSEC-Q
Processing
Changes the set value (SV) to the
value that was in Set value monitor
(buffer memory address: 25, 26) right
before the control shift.
Changes the set value (SV) of the
slave channel to the value that was
in CH2 Set value monitor (buffer
memory address: 26) right before the
control shift. The set value (SV) of
the master channel does not change.
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