A6.4.1 Mode Handling; A6.4.2 Status Handling - YOKOGAWA digitalYEWFLO Series User Manual

A6.4.1 Mode Handling

Mode
Auto OUT = PRE_OUT
MAN
For OUT, the OUT value in the Auto mode just before
change to MAN or O/S is retained.
O/S
In the Manual mode (including O/S), the value of
OUT in the Auto mode just before a change to the
Manual mode is held or the value written to OUT is
output.
If the mode is switched from Manual to Auto, the
value of OUT that is linearly changed with respect to
the value of PRE_OUT for time set by BAL_TIME is
output. The PRE_OUT always indicates the results
of calculation. After elapse of BAL_TIME, OUT =
PRE_OUT is established. Note that if the value
of BAL_TIME is changed during linear change
of the OUT value, it is not reflected. The value of
BAL_TIME will be reflected only after the mode is
changed the next time.
AUTO MAN
PRE_OUT
Case of BAL_TIME = 5 sec
OUT
The value of OUT is represented by the following
equation.
y = y + (x -y
n n-1 n n-1
α = (T / t ) + 1
c
*: The value of T/tc truncates digits to the right of
the decimal point.
where y : OUT
x : PRE_OUT
t : period of execution
c
T : BAL_TIME
n : period
<APPENDIX 6. Enhanced ARITHMETIC (AR) BLOCK>
Output
AUTO
BAL_TIME
FA0604.ai
) / (α - n)

A6.4.2 Status Handling

The setting of INPUT_OPTS is applied to the input
status. When INPUT_OPTS is applied, there are
cases where the PV status becomes "good" even if
the status of main inputs is "uncertain" or the status
of auxiliary inputs is "uncertain" or "bad."
The PV status is classified by the following:
• If the statuses of two main inputs are both
"good" or anything other than "good":
Read APPENDIX 6.2.1 "Main Inputs"
• If only one of the statuses of two main inputs is
"good":
• If the status of IN is "good" and that of "IN_
LO" is anything other than "good"
IN > RANGE_LO → The status of IN
IN ≤ RANGE_LO → Read APPENDIX 6.2.1
• If the status of IN is anything other than
"good" and that of "IN_LO" is "good"
IN_LO < RANGE_H → The status of IN_LO
IN_LO ≥ RANGE_HI → Read APPENDIX
The exception is that if RANGE_LO > RANGE_HI,
the PV status is made "Bad. Configuration Error."
The input status irrelevant to the computing
equation selected by ARITH_TYPE will be ignored
and does not affect other statuses. The statuses
of outputs (OUT.Status and PRE_OUT.Status) are
interpreted as the status of the worst input among
the statuses of PV and auxiliary inputs (IN_1,
IN_2, and IN_3) to which INPUT_OPTS has been
applied.
Example: If input status and INPUT_OPTS has
been applied
Case 1
PV
IN_1
IN_2
IN_3
Handled as a
"good" input if
IN_1
its status is
INPUT_
"uncertain."
OPTS
Handled as a "good" input if its
IN_2
status is "bad."
IN_3
1) Flow compensation (linear) in APPENDIX
ARITH_TYPE
6.3.1 "Computing Equations"
OUT.Status Good
A6-6
applies.
"Main Inputs"
applies.
6.2.1 "Main Inputs"
Case 2 Case 3
Good
Uncertain
Bad
Bad
No option
No option
No option
Uncertain Bad
IM 01F06F00-01EN