Remark
The proportional band (P) is the variation width of deviation (E) necessary for manipulated value (MV) to vary 0% to 100%.
The following formula shows the relationship between deviation (E) and manipulated value (MV) in proportional action.
Kp is proportional gain. The following formula shows proportional band (P) in this case.
When the value of the proportional band (P) is increased, the proportional gain (Kp) decreases. Therefore, the manipulated
value (MV) for variation of the deviation (E) becomes small.
When the value of proportional band (P) is decreased, the proportional gain (Kp) increases. Therefore, the manipulated
value (MV) for variation of the deviation (E) becomes large. The following figure shows the proportional band (P) in reverse
action.
Manipulated value
(MV)
100%
Manipulated
value (MV) to
deviation (E)
0%
Current temperature
process value (PV)
MV = Kp E
1
P =
100
Kp
Deviation
(E)
Set value
(SV)
Proportional band (P)
APPENDICES
Temperature
process value
(PV)
A
319