YOKOGAWA UP750, User Manual

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<Toc> <3. Programming>
3-29
IM 05E01B02-41E 1st Edition : May 31,2000-00
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Selecting PID Constants According to the Deviation
PID constants can be selected according to the deviation in two ways. One method is to
select a group of PID constants only by a deviation from a program setpoint. The other
method is to use a reference point, as discussed earlier, as well as a deviation from a
program setpoint, to switch between groups of PID constants.
[Method 1]
As shown in the figure below, the controller selects the PID constants of the group number
set in PID group number (GRP) if the PV input value goes beyond the given deviation from
the program setpoint.
[1] The controller uses the 1st group of PID constants.
[2] The controller uses the PID constants of the group number set in PID group number
(GRP).
Reference
deviation (RDV1)
Maximum value of
PV input range (RH1)
Minimum value of
PV input range (RL1)
Program setpoint
Segment 1 Segment 2
PV input value
Reference
deviation (RDV1)
[1]
[2]
[2]
[1]
[1]
[2]
[Method 2]
As shown in the figure below, the controller selects an appropriate group of PID constants
for each zone and, if the PV input value goes beyond the given deviation from the program
setpoint, selects the PID constants of the group number set in PID group number (GRP).
[1] The controller uses the 1st group of PID constants if the PV input value is both within
the zone set off by the minimum value of the PV input range and reference point 1 and
within the given reference deviation bandwidth.
[2] The controller uses the 2nd group of PID constants if the PV input value is both within
the zone set off by reference points 1 and the maximum value of the PV input range,
and within the given reference deviation bandwidth.
[3] The controller uses the PID constants of the group number set in PID group number
(GRP).
Reference point 1
(1.RP1)
Reference
deviation (RDV1)
Maximum value of
PV input range (RH1)
Minimum value of
PV input range (RL1)
Segment 1 Segment 2
Reference
deviation (RDV1)
Program setpoint
PV input value
[1]
[3]
[3]
[2]
[2]
[1]
[3]