Rosemount OCX 8800, Instruction Manual

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Instruction Manual
IM-106-880, Rev 2.1
April 2017
OCX 8800
7-61
Application Information
The ISEL function block can be used to select the maximum temperature
input from four inputs and send it to a PID function block to control a process
water chiller (Table 7-28) or it can use the block to calculate the average
temperature of the four inputs (Table 7-29).
Figure 7-28. Input Selector
Function Block Application
Example (SEL_TYPE = max).
Figure 7-29. Input Selector
Function Block Application
Example (SEL_TYPE = avg.).
Figure 7-30. Input Selector
Function Block Application
Example (SEL_TYPE = Hot
Backup)
IN1 = 126°F
IN2 = 104°F
IN3 = 112°F
IN4 = 130°F
IN1 = 126°F
IN2 = 104°F
IN3 = 112°F
IN4 = 130°F
IN1 = 126°F
IN2 = 104°F
IN3 = 112°F
IN4 = 130°F
To Another
Function Block
To Another
Function Block
Table 7-36. Input Selector
Function Blocks
Time Value
IN1
Status Value
IN2
Status Value
Out
Status
Selected
Value Status
T
0
Good 20 Good 21 Good 20 Good 1
T
1
Bad 20 Good 21 Good 21 Good 2
T
2
Good 20 Good 21 Good 21 Good 2
The instrument must be in Manual or Out of Service mode to set the status option.
Input Selector
(ISEL) Function
Block
SEL_TYP = Hot Backup
3
9
9
3
0
0
2
8
3
9
9
3
0
0
2
7
3
9
9
3
0
0
2
6
Input Selector
(ISEL) Function
Block
OUT = 130°F
Input Selector
(ISEL) Function
Block
OUT = 118°F
SEL_TYP = avg