User`s manual
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MELSEC-Q
8 I/O CONTROL INSTRUCTIONS
(2) Execution cycle ( T)
Set the execution cycle in SD1500 and SD1501 as real numbers.
Processing contents
(1) Mode judgment
Either of the following processings is performed depending on the operation mode (MODE).
(a) When the operation mode (MODE) is any of MAN, CMB, CMV and LCM (alarm clear
processing)
1) MHA, MLA and DMLA of the alarm detection (ALM) are turned to 0.
2) BB1 to BB4 of BB are turned to 0.
3) "(3) Output conversion processing" is performed and the S.OUT2 instruction is
terminated.
(b) When the operation mode (MODE) is any of AUT, CAB, CAS, CCB, CSV, LCA and LCC,
"(2) Change rate, upper/lower limiter" is performed.
However, when SEA of the alarm detection (ALM) is 1 and SM1501 is ON (with hold), BB1
to BB4 are turned to 0 and the S.OUT2 instruction is terminated.
(2) Change rate, upper/lower limiter
Change rate and upper/lower limit checks are performed on a difference between the
temporary MV (T) and manipulated value (MV), and the data and alarm are output after the
limiter processings.
(a) The change rate limiter performs the following operation and outputs the result of the
operation to BB4 and DMLA.
Condition BB4, DMLA Result (T1)
|
E1
MV
|
DML 0 E1
(E1
MV)
DML 1
*1
MV DML
(E1
MV)
DML 1
*1
MV DML
*1: When DMLI or ERRI in the alarm detection inhibition (INH) is set to 1, DMLA and BB4 show 0
since the alarm is prohibited.
(b) The upper/lower limiter performs the following operation and outputs the result of the
operation to BB2, BB3, MHA and MLA.
Condition BB3, MLA BB2, MHA MV
T1 MH 0 1
*2
MH
T1 ML 1
*3
0ML
ML T1 MH 0 0 T1
*2: When MHI or ERRI in the alarm detection inhibition (INH) is set to 1, MHA and BB2 show 0 since
the alarm is prohibited.
*3: When MLI or ERRI in the alarm detection inhibition (INH) is set to 1, MLA and BB3 show 0 since
the alarm is prohibited.
(3) Output conversion
In the output conversion, the output value is calculated from the following formula.
100
NMAX NMIN
BW
MV
NMIN