Yokogawa Data Acquisition with PID Control CX2000 - Manual (Page 42)

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IM 04L31A01-01E
1.6 Target Setpoint Related Settings
Setting the SP
Set the SP, as one of the PID parameters, for each PID number (1 to 8) in the range of
EU (0.0 to 100.0% of the measurement span). The PID number in which the SP has
been registered is handled as “SP number” when specifying the setpoint and for other
purposes.
SP Assignment
The SP is specified using the SP number. The operation at the time of SP number
switching varies depending on the PID selection method.
• When target setpoint selection method is selected
The SP number and PID number are synchronized. By switching the SP number, the
control parameters (“PID parameters” in the settings) such as the SP and the PID
constant are changed to the control parameters registered to the corresponding PID
number.
SP1
(No.1PID)
SP3
(No.3PID)
SP1
(No.1PID)
SP2
(No.2PID)
PV
Rise according to
the setpoint
ramp-up setting
SPn: SP number
Rise according to
the setpoint
ramp-up setting
Switch from SP1 to SP3 Switch from SP3 to SP1 Switch from SP1 to SP2
Time
Fall according to
the setpoint
ramp-down setting
• When zone PID method is selected
The assignment of the SP number and the assignment of the PID number are not
synchronized.
A PID number (group number of the PID parameter) is registered for each zone
beforehand. When the PV changes and becomes a value of a different zone, the PID
number automatically changes, but the SP number does not switch.
Note
The value of control alarms corresponds to the SP number (see section 4.7 ). If the SP
number is changed, the alarm value also changes accordingly.
Selection of the SP Number to Be Switched Using Contact Input
Set loop 1 to 6 for switching the SP number using the contact input “Set target setpoint
bits 0 to 3” (see page 1-27).
Target Setpoint Tracking
The CX2000 can perform operation according to the remote SP (remote input) received
from an external source. In this case, it is foreseeable that the output value will
drastically change when switching from a remote operation condition to a local operation
(operation according to the internal SP of the CX2000) condition or switching from
program operation to local operation. To prevent the output value from drastically
changing, the CX2000 has a function used to track the output from the remote SP to the
local SP. The operation image of target setpoint tracking is shown below.
PV
Local SP
Remote SP
• When target setpoint tracking is enabled
Switch from remote to local mode
Time Time
• When target setpoint tracking is disabled
Switch from remote to local mode
Local SP
Remote SP
PV