Mitsubishi Electric MELSEC iQ-F FX5 User Manual page 359

■Operation
[Operation performed when an alert is output]
Digital output values are monitored on the rate alarm alert detection cycle. When a change rate of a digital output value (from
a previous value) is equal to or more than the rate alarm upper limit value, or the rate is equal to or less than the rate alarm
lower limit value, an alert is output as follows.
• Alarm ON (1) is stored in 'Alert output flag (Rate alarm upper limit)' (Un\G38) or 'Alert output flag (Rate alarm lower limit)'
(Un\G39).
• 'Alert output signal' (Un\G69, b8) turns on.
• The ALM LED turns on.
• An alarm code is stored in 'Latest alarm code' (Un\G2). (Page 417 List of alarm codes)
The conversion on a channel where an alert was output continues.
[Operation after an alert was output]
After an alert was output, if the change rate of a digital output value does not satisfy the alert output conditions due to being
smaller than the rate alarm upper limit value or being greater than the rate alarm lower limit value, Normal (0) is stored in a bit
corresponding to the channel of 'Alert output flag (Rate alarm upper limit)' (Un\G38) or 'Alert output flag (Rate alarm lower
limit)' (Un\G39).
In addition, when all 'Alert output flag (Rate alarm upper limit)' (Un\G38) and 'Alert output flag (Rate alarm lower limit)'
(Un\G39) return to Normal (0), 'Alert output signal' (Un\G69, b8) turns off and the ALM LED turns off. However, the alarm code
stored in 'Latest alarm code' (Un\G2) is not cleared. Turn offonoff 'Error clear request' (Un\G70, b15) to clear the alarm
code.
■Detection cycle
The rate alarm alert detection cycle is calculated by the following formula.
• Rate alarm alert detection cycle = Conversion cycle  Setting value of 'CH1 Rate alarm alert detection cycle setting'
(Un\G522)
Ex.
CH1: Current (4 to 20 mA), CH2 to 6: Conversion disabled, CH7: Pt100, CH8: When setting the input range to K and making
the following settings
• 'CH1 Rate alarm alert detection cycle setting' (Un\G522): 5 (times)
• 'CH7 Rate alarm alert detection cycle setting' (Un\G1722): 8 (times)
The CH1 rate alarm alert detection cycle is 5 ms. (1 ms  1 (CH)  5 (times))
The CH7 rate alarm alert detection cycle is 640 ms. (40 ms  2 (CH)  8 (times))
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3.4 Functions