50 PROSEC T3H
2. Expanded Functions
• Manual mode
In this mode, the manipulation value MV can be directly controlled by the input value of MMV.
MV differential limit for manual mode DMMV is effective. MH/ML and DMV are not effective.
When mode is changed from manual to auto or cascade, the operation is started from the current MV.
• Cascade mode
This is a mode for PID cascade connection. PID is executed with CSV as set value.
Different from the auto mode, set value differential limit is not effective. Manipulation value upper/lower
limit MH/ML and differential limit DMV are effective.
Bump-less changing from cascade mode to manual mode is available. (Manual mode m anipulation
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 available in auto and cascade modes. When the tracking designation (A+5 bit 2) is ON,
tracking input TMV is directly 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-program.
• PID3 instruction must be used under the constant scan mode. The constant scan interval can be selected
in the range of 10 to 200 ms, 10 ms increments.
• 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 instruction (FUN165 FG) is convenient.