Mitsubishi Electric MELSEC-Q series User Manual page 55

(2) Rate alarm
When a change rate of a digital output value is equal to or more than the rate alarm upper limit value (%/s) or that
is equal to or less than the rate alarm lower limit value (%/s), an alert is output.
Digital output
value
Change rate of
digital output
value (%)
CH1 Warning output flag
(Rate alarm upper limit
value) (Un\G51.b0)
CH1 Warning output flag
(Rate alarm lower limit
value) (Un\G51.b1)
Warning output signal (X8)
(a) Operation of warning output
Digital output values are monitored in each set rate alarm warning detection period. A change rate of the digital
output value compared to the previous value is equal to or more than the rate alarm upper limit value (%/s) or
that equal to or less than the rate alarm lower limit value (%/s), an alert is output as follows.
• Alarm ON (1) is stored in Warning output flag (Rate alarm) (Un\G51).
• Warning output signal (X8) turns on.
• The ALM LED turns on.
• Alarm code 10  is stored in Latest error code (Un\G19).
Alarm codes are stored as below.
10
Fixed
However, the digital conversion continues on the channel where an alert was output.
Rate alarm
warning
CH1 Digital output value
detection
period
Rate alarm
warning
detection
period
0
ON
OFF OFF
OFF
ON
OFF OFF
Rate alarm channel number
2: Rate alarm upper limit
3: Rate alarm lower limit
CHAPTER 4 FUNCTIONS
Time
Rate alarm
upper limit
Change of
value
CH1 Digital
output value
Time
Rate alarm
lower limit
value
ON
OFF
ON
OFF
Executed by the CT input module
4
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