Yokogawa EJX930A - Manual (Page 107)

<Appendix 3. Input Selector (IS) Block>
A3-12
IM 01C25T02-01E
A3.4 Output Processing
A3.4.1 Handling of SELECTED
For the value output to SELECTED when OP_SELECT has been selected (that is, not “0”), the number
specified by OP_SELECT will be stored as is.
However, “0” is stored in the SELECTED in the following cases:
1. If there is no valid input;
2. If the value of MIN_GOOD is greater than the number of valid inputs;
3. If the input status is “bad” or “uncertain” when the value of OP_SELECT is anything other than “0”
(with the exception of the case where the “Uncertain as good” bit in STATUS_OPTS is set.);
4. If the value of OP_SELECT is greater than 8, which is the maximum number of inputs;
5. If the value is out of the SELECT_TYPE setting range when the value of OP_SELECT is zero.
As long as there is one valid input, even an invalid input can be selected for OP_SELECT.
If the number of valid inputs is greater than the value of MIN_GOOD, the number of the input (including an
invalid input) specified by OP_SELECT will be stored in SELECTED. Therefore, even if an invalid input is
selected, SELECTED does not become zero.
If no input is selected for OP_SELECT, the output of SELECTED will depend on SELECT_TYPE.
The Table A3.1 shows the value of SELECTED according to the number of valid inputs and SELECT_TYPE.
Table A3.1 Value of SELECTED According to Inputs
Valid Inputs
Value of SELECTED
SELECT_TYPE =
First Good
SELECT_TYPE =
MINIMUM, MAXIMUM,
or Latched Good
SELECT_TYPE =
MIDDLE
SELECT_TYPE =
AVERAGE
None 0 (zero) 0 (zero) 0 (zero) 0 (zero)
1 # of IN with a smaller
value
# of selected IN # of selected IN 1
Multiple INs
(Even # of INs)
0 (the average is taken) # of valid INs
(the average is taken)
Multiple INs
(Odd # of INs)
# of IN with the middle
value
Table A3.2 Value of SELECTED According to the Mode
O/S MAN AUTO
0 0 0 to 8