Omron E5EK, User Manual

Page: 69 / 203

4.2 Operating Condition Restrictions
E5EK
4--7
4.2 Operating Condition Restrictions
The upper- and lower-limit values of the manipulated variable can be
restricted by the MV limitter, and the change rate of manipulated vari-
able can be restricted by the MV change rate limitter.
The upper- and lower-limit values of the manipulated variable are set
in the “MV upper limit” and “MV lower limit” parameters (level 2
mode). When the manipulated variable calculated by the E5EK-T is out-
side of the range of the MV limitter, actual outputs are dependent on
the set value of these parameters.
100
0
PV
Output (%)
MV upper limit value
MV lower
limit value
In heating and cooling control, the manipulated variable at the cooling
side is treated as a negative value for the sake of convenience. The up-
per limit is set for the heating side (positive value), and the lower limit
is set for the cooling side (negative value) as shown in the following fig-
ure.
100
0
PV
Output (%)
MV upper limit value
MV lower limit value
Heating
side
Set point
Cooling
side
The “MV change rate limitter” parameter (level 2 mode) sets the maxi-
mum permissible change width per second of the manipulated variable.
If a change in the manipulated variable exceeds this parameter setting,
the value calculated by the E5EK-T is reached while changing the value
by the per-second value set in this parameter.
100
0
Output (%)
Switching point
Time
MV change rate
limit value
1 second
J
Manipulated vari-
able restrictions
F
MV limiter
F
MV change rate
limiter