C2-12
IM 34M06H62-02E 2nd Edition : June 2008-00
Rate-of-change Limit
The rate-of-change limit prevents drastic changes in the output by defining the maximum
rate of change allowed in the control output. This function is useful for protecting a
controlled load or machine.
For example, supposing that the rate-of-change is set to 2% per second, even if the PID
computation result changes instantly from 0 to 100%, the actual output changes linearly
from 0 to 100% over a duration of 50 s.
Figure C2.6 Rate-of-change Limit
Table C2.12 Rate-of-change Limit Parameter
Data Position Number
Symbol Description Unit
Data Range
Default
Value
Attribute
Stored
Loop 1 Loop 2 Loop 3 Loop 4
193 393 593 793 MVR Rate-of-change limit %/s
0: OFF
1 to 1000 (0.1 to 100.0% per second)
0 RW
The rate-of-change limit is disabled in the following situations:
- When the Run/Stop Selection is set to Stop
- When the Automatic/manual/cascade Selection is set to Manual
- If burnout or AD converter error is detected when the Automatic/manual/cascade
Selection is set to Automatic (see Section C10, "Self-diagnosis Function")
- When heating/cooling PID control is selected.
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