Manual Reset Function - Mitsubishi Electric MELSEC iQ-R Series User Manual

1.7

Manual Reset Function

This function is used to manually move a stable position in the P control or PD control.
An offset (remaining deviation) is manually reset by moving the proportional band (P).
The offset is reset by determining and setting the amount to shift the manipulated value (MV) in a stable condition from the
reference value.
The reference value is 50% for the standard control, and 0% for the heating-cooling control.
This function can be used only in the P control and PD control. This function is disabled when the integral time
(I) is set to a value other than 0.
'CH1 Manual reset amount setting' (Un\G517) is ignored even though a value has been set. (However, when
a value out of the setting value is set, an out of setting range error (error code: 1950H) occurs.)
Standard control
The set value (SV) is set at a point where the manipulated value (MV) is 50%. Thus, as long as the temperature process value
(PV) and the set value (SV) are not balanced at 50% of the manipulated value (MV), an offset (remaining deviation) is
generated.
When an offset is generated, the proportional band (P) can be manually shifted by the amount of the offset (remaining
deviation).
Ex.
When using the manual reset function in the following conditions
• Control method: P control
• 'CH1 Manual reset amount setting' (Un\G517): 300 (30%)
The temperature control module shifts the manipulated value (MV) in a stable condition at the set value (SV) from 50% to
80%.
100%
80%
Manipulated value
(MV)
50%
0%
1 FUNCTIONS
32
1.7 Manual Reset Function
Proportional band
(P)
(Percentage to the full scale)
Manual reset
The manipulated value (MV)
can be moved from 50% to 80%
to keep the set value (SV) stable.
Set value (SV)
Manual reset range: -100.0 to 100.0% (every 0.1%)
(Set -1000 to 1000)
Input range
Configure the settings
as follows:
Integral time (I): 0
Derivative time (D): 0