Mitsubishi MELSEC iQ-F, User Manual

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4 FUNCTIONS
4.7 Alert Output Function
Ex.
The judgment under the following conditions
In the above case, the current digital output value and the previous digital output value (digital output value of 5 ms before) are
compared at each rate alarm warning detection cycle of 5 ms (1 ms
× 5 times). As a result of the comparison, it is judged
whether the increase of the digital output value is 8000 (= 250 × 0.1 × 0.01 × 32000) digit or more or 1600 (= 50 × 0.1 × 0.01 ×
32000) digit or less.
■
When the rate alarm change rate selection is "Digital output value specification"
It is judged by comparing the difference between the current digital output value and the digital output value in the previous
detection cycle with the rate alarm upper limit value and the rate alarm lower limit value.
*1 When the input type is "RTD" or "Thermocouple", set the rate alarm upper limit (lower limit) in unit of 0.1  .
Ex.
The judgment under the following conditions
In the above case, the current digital output value and the previous digital output value (digital output value of 200 ms before)
are compared at each rate alarm warning detection cycle of 200 ms (40 ms
× 5 times). From the comparison, whether the
increase in the digital output value is 10000 (1000.0  ) or more, or 3200 (320.0  ) or less is judged.
Detection target for outputting an alert
'CH1 Digital output value' (Un\G400) is a target for outputting an alert. The target is the same for when the scaling function is
enabled.
Setting item Setting content
Conversion enabled channels CH1
CH1 Input type/range setting Current (4 to 20 mA)
Rate alarm change rate selection Rate specification
CH1 Average processing specification Sampling processing
CH1 Rate alarm alert detection cycle setting 5 times
CH1 Rate alarm upper limit value 250 (25.0%)
CH1 Rate alarm lower limit value 50 (5.0%)
Alarm occurrence condition Conversion formula
For alert outputting of rate alarm upper limit Current digital output value - Digital output value at the previous detection cycle
≥
Rate alarm upper limit value
*1
For alert outputting of rate alarm lower limit Current digital output value - Digital output value at the previous detection cycle ≤ Rate alarm lower limit value
*1
Setting item Setting content
Conversion enabled channels CH1
CH1 Input type/range setting Pt100
Rate alarm change rate selection Digital output value
CH1 Average processing specification Sampling processing
CH1 Rate alarm alert detection cycle setting 5 times
CH1 Rate alarm upper limit value 10000 (1000.0  )
CH1 Rate alarm lower limit value 3200 (320.0  )