Yokogawa Data Acquisition with PID Control CX2000 - Manual (Page 55)

1-43
IM 04L31A01-01E
Explanation of Functions
3
2
1
4
5
6
7
8
9
10
11
12
13
14
PV
Operation of
segment 1 to 99
Time
Final SP
1min or
1h
Final SP of the
previous segment
(Starting SP at thetime
of program operation start)
Ramp-rate setting
During ramp-up
The segment assignment method applies to all segments constructing the program
pattern. Note that the contents of all program patterns created before are cleared when
the segment assignment method is changed.
Selecting the Start Condition for Program Operation
The following four operation start conditions (start codes) are available for selection.
• Starting SP start (initial value).
• Ramp-prioritized PV1 start
• Time-prioritized PV start
• Ramp-prioritized PV2/3/4/5/6 start
Starting Target Setpoint Start
The starting SP is the SP at the start of the program operation.
When set to starting SP start, the SP is changed from the starting SP to the final SP. In
this case, the change follows the ramp-rate defined by “(final SP – starting SP)/segment
time” regardless of the PV. When segment time ramp-rate assignment method is
selected, the change follows the specified ramp-rate.
PV
SEG1 SEG2
TSPn: Final SP
SSPn: Starting SP
Time
TSP2
SSP2
SSP1
TSP1
Program pattern for
the 1st loop
Program pattern for
the 2nd loop
Segment time
Ramp-prioritized PV Start
In ramp-prioritized PV start, the program operation is started by specifying one of the
process values (PV1 to PV6) of loops 1 to 6. The patterns of other unspecified patterns
start according to the PV start pattern of the specified loop. The start point varies
depending on the comparison between the starting PV of the specified loop and the SP
specified by the program pattern. The section of the program pattern that is compared is
from the starting SP to the first soak point or the first ramp-down start point (when the
start segment is ramp-up). The start point is the point at which the starting PV value and
the setpoint on the program pattern match. If this matching point is not found, the start
point is the end point of the program pattern being compared against.
If the segment consists of only an up ramp and the starting PV is greater than the final
SP, the program control will not start and program control ends. In this case, SP
tracking prcess is not performed. If the start segment is a soak, this function does not
operate, and the start condition is the same as with the starting SP start.
Loops set to ramp-prioritized PV start that are in local or stopped mode and are no
longer in program operation mode, change to starting SP start.
Below are examples of ramp-prioritized PV1 start and ramp-prioritized PV2 start.
1.11 Program Control Related Settings