User`s manual

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MELSEC-Q
8 I/O CONTROL INSTRUCTIONS
Processing contents
(1) Range check
(a) A range check is performed on the input value (E1).
An alarm is output if the input value (E1) exceeds the upper/lower limit value.
Range check result (alarm output)
Range check Condition
BB2 BB3 BB1, SEA
E1 HH 1
*1
1
*1
E1 H0 0
Upper limit
check
H E1 HH Last value Last value
E1 LL 1
*1
1
*1
E1 L 00
Lower limit
check
LL
E1 L Last value Last value
*1: When SEI or ERRI in the alarm detection inhibition (INH) is set to 1, SEA, BB1, BB2 and BB3
show 0 since the alarm is prohibited.
(b) Last value hold processing
When a range excess occurs (BB1
1) in the range check, whether operation will be
continued unchanged or the S.IN instruction will be terminated is judged depending on
whether SM1500 is ON or OFF.
1) When SM1500 is OFF (not in the hold mode), "(2) Input limiter processing" is performed
if a range excess occurs (BB1
1).
2) When SM1500 is ON (in the hold mode), the following processing is performed and the
S.IN instruction is terminated if a range excess occurs (BB1
1).
• BW retains the last value.
• Error information is set in BB.
(2) Input limiter processing
Upper/lower limiter setting is made on the input value (E1).
Condition Result (T1)
E1 NMAX NMAX
E1 NMIN NMIN
NMIN E1 NMAX E1