Mitsubishi MELSEC Q Series User Manual page 54

3 SPECIFICATIONS
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(c) Set the rate alarm upper limit value/lower limit value in 0.1%/s increments
relative to the maximum value (64000) of the digital output value.
The setting range is -65536 to 65535 (-6553.6% to 6553.5%).
(d) The setting range of the rate alarm warning detection period is 10 to
5000ms.
When the period is set to 5000ms, the digital values are compared at
intervals of 5 seconds to detect the varying rate.
(e) The rate alarm is judged by converting the rate alarm upper/lower limit
value into the digit value per rate alarm warning detection period.
The conversion expression of the value used to make judgment per rate
alarm warning detection period is as follows.
Value used to make judgment per rate alarm warning detection period [digit]
=rate alarm upper limit value or lower limit value
alarm warning detection period ÷ 1000
Example
When the varying rate upper limit value of channel 1 is set to 30%/s (300 is
stored into the buffer memory) and the rate alarm warning detection period of
channel 1 is 10ms, the current and previous values are compared at intervals of
10ms and whether or not the value has varied 0.3% (192 digits) or more in 10ms
is judged.
300 0.001 64000 10÷1000=192(digit)
(f) The rate alarm is useful to watch the varying rate of the digital output value
in the limited range.
1) Example of setting the rate alarm upper limit value/lower limit value
when it is desired to watch that the digital output value is at the rise rate
within the specified range
Varying rate (%) of
digital output value
+30%
+20%
0
0.001
Rate alarm upper limit value
Rate alarm lower limit value
MELSEC-Q
64000 rate
Time
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