User`s manual

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MELSEC-Q
9 CONTROL OPERATION INSTRUCTIONS
(2) Upper/lower limit check
The upper/lower limit checks of the input value (E1) are made under the following conditions.
Check item Condition ALM BB2 BB3
E1 PH’ PHA 1
*1
1
*1
E1 PH’ HS PHA 00Upper limit check
Others PHA: Last value is status hold
*1
Hold
*1
E1 PL’ PLA 1
*2
1
*2
E1 PL’ HS PLA 0 0
Lower limit check
Others PLA: Last value is status hold
*2
Hold
*2
E1 HH’ HHA 1
*3
E1 HH’ HS HHA 0
Upper Upper limit
check
Others HHA: Last value is status hold
*3
E1 LL’ LLA 1
*4
E1 LL’
HS LLA
0
Lower lower limit check
Others LLA: Last value is status hold
*4
*1: When PHI or ERRI in the alarm detection inhibition (INH) is set to 1, PHA and BB2 show 0 since the
alarm is prohibited.
*2: When PLI or ERRI in the alarm detection inhibition (INH) is set to 1, PLA and BB3 show 0 since the
alarm is prohibited.
*3: When HHI or ERRI in the alarm detection inhibition (INH) is set to 1, HHA show 0 since the alarm is
prohibited.
*4: When LLI or ERRI in the alarm detection inhibition (INH) is set to 1, LLA show 0 since the alarm is
prohibited.
(3) Change rate check
(a) A change rate check is performed for the time specified in CTIM.
The number of change rate checks to be made is found by the following expression.
CTIM
T
m
m varies from 1 to m.
However, when m
0 (integer part), no processing is performed.
For example, when m
4, the processing is performed as shown below.
E1
n
E1
n
1
E1
n
2
E1
n
3
E1
n
4
abcde
CTIM
Execution cycle
DPL
t
(a) Zero time E1
n
E1
n-4
(b) One time E1
n+1
E1
n
(c) Two time E1
n+2
E1
n
(d) Three time E1
n+3
E1
n
(e) Four time E1
n+4
E1
n