6F3B0253
Basic Hardware and Function 223
7. Instructions
Manual mode
In this mode, the manipulat ion value MV can be directly controlled by the input value of MMV.
MV differential limit for manual mode DMMV is effect ive. MH/ML and DMV are not effect ive.
When mode is changed from manual to auto or cascade, the operation is started from the c urrent MV.
Cascade mode
This is a mode for PID cascade connect ion. PID is executed with CSV a s set value.
Different from the auto mode, set value differential limit is not effect ive. Manipulation value upper/lower
limit MH/ML and differential limit DMV ar e effective.
Bump-less changing from cascade mode to manual mode is av ailable. (Manual m ode manipulation
value MMV is over-written by current MV automatically. MMV MV)
And, bump-less changing from cascade mode to auto mode is available. (Auto mode set value ASV is
over-written by current CSV automatically. ASV CSV)
MV tracking
This function is av ailable in auto and cascade modes. When the tracking desi gnation (A+5 bit 2) is ON,
tracking input TMV is directl y output as MV.
Manipulation value upper/lower limit MH/ML is effective, but differential limit DMV is not effective.
When the tracking designation is changed to OFF, the operation is started from the current MV.
Note
PID3 instruction is only usable on the main-progra m.
PID3 instruction must be used under the constant sc an mode. The constant scan interval can be selected
in the range of 10 to 200 ms, 10 ms incr ements.
The data handled by the PID3 instruction are % units. Therefore, process input value PVC , manipulation
value MV, etc., should be converted to % units (scaling), before and/or after the PID3 instruction. For this
purpose, the function generator instru ction (FUN165 FG) is convenient.