Mitsubishi Electric Melsec iQ-R Series User Manual page 38

Operation
■Operation performed when a warning is output
Digital output values are monitored every rate alarm warning detection cycle. When a change rate of a digital output value
(from a previous value) is equal to or greater than the rate alarm upper limit value, or the rate is equal to or smaller than the
rate alarm lower limit value, a warning is output as follows.
• Alarm ON (1) is stored in 'Warning output flag (Rate alarm upper limit)' (Un\G38) or 'Warning output flag (Rate alarm lower
limit)' (Un\G39).
• 'Warning output signal' (X8) turns on.
• The ALM LED turns on.
In addition, an alarm code is stored in 'Latest alarm code' (Un\G2).
For details on the alarm codes, refer to the following.
Page 82 List of Alarm Codes
The A/D conversion on a channel where a warning was output continues.
■Operation after a warning was output
After a warning was output, if the change rate of a digital output value does not satisfy the warning 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 number of 'Warning output flag (Rate alarm upper limit)' (Un\G38) or 'Warning output flag
(Rate alarm lower limit)' (Un\G39).
In addition, when all 'Warning output flag (Rate alarm upper limit)' (Un\G38) and 'Warning output flag (Rate alarm lower limit)'
(Un\G39) return to Normal (0), 'Warning output signal' (X8) turns off and the ALM LED turns off. However, the alarm code
stored in 'Latest alarm code' (Un\G2) is not cleared. To clear the alarm code, turn on and off 'Error clear request' (YF) after all
the bits of 'Warning output flag (Rate alarm upper limit)' (Un\G38) and 'Warning output flag (Rate alarm lower limit)' (Un\G39)
return to Normal (0).
Detection cycle
Set the rate alarm warning detection cycle in 'CH1 Rate alarm warning detection cycle setting' (Un\G522).
The rate alarm warning detection cycle is the value calculated by multiplying the set value by the conversion cycle.
Ex.
The cycle to detect a rate alarm warning is 800ms (80ms  10 (times)) when 'CH1 Rate alarm warning detection cycle setting'
(Un\G522) is set to 10 (times).
Digital output values are compared in 800ms intervals to check the change rate.
An analog input signal that has reached the A/D converter is smoothed. Thus, if a shorter time than the
response time (400ms) is set as a rate alarm warning detection cycle and the set change rate of a detection
condition is large, rate alarm may not be detected. When setting a shorter time than the response time
(400ms) as the warning detection cycle, set 'CH1 Rate alarm upper limit value' (Un\G524) and 'CH1 Rate
alarm lower limit value' (Un\G526) to be low so that rate alarm can be detected for even a smoothed analog
input signal.
1 FUNCTIONS
36
1.8 Warning Output Function