Mitsubishi Electric R60AD8-G User Manual page 37

Judgment of rate alarm
A change rate is judged with 'CH1 Rate alarm upper limit value' (Un\G524) and 'CH1 Rate alarm lower limit value' (Un\G526)
converted to digital values per rate alarm alert detection cycle.
The following shows the conversion formula of judgment values used for the rate alarm detection.
Value used for judgement at each Rate alarm alert detection cycle [digit] =
Item
R
H
R
L
D
Max
Values after the decimal point are omitted.
Ex.
The judgment value under the following conditions
• Input range: 4 to 20mA
• A/D conversion-enabled channel: CH1
• 'CH1 Averaging process specification' (Un\G501): Sampling processing (0)
• 'CH1 Rate alarm alert detection cycle setting' (Un\G522): 5 (times)
• 'CH1 Rate alarm upper limit value' (Un\G524): 250 (25.0%)
• 'CH1 Rate alarm lower limit value' (Un\G526): 50 (5.0%)
250
Upper limit value: × 32000 = 8000 (digit)
1000
50
Lower limit value: × 32000 = 1600 (digit)
1000
The present value is compared to the previous value (50ms) in a rate alarm alert detection cycle of 50ms (sampling period
10ms  5). A digital value is judged if it increases 8000 digits (25.0%) or more, or if the increase is 1600 digits (5.0%) or less
from the previous value (when the maximum digital output value is 32000).
Use the following formula to calculate a change rate to be set based on the change amount of voltage and current to detect an
alert.
Change rate to be set (0.1%) =
*1 Values after the decimal point are omitted.
R
H
1000
Description
Rate alarm upper limit value (Unit: 0.1%)
Rate alarm lower limit value (Unit: 0.1%)
Maximum digital output value of the input range
• Other than extended mode: 32000
• Extended mode: 36000
Change amount of the voltage (current) to detect an alert (V(mA))
Gain voltage (current) (V(mA)) - Offset voltage (current) (V(mA))
or R
L
× D
Max
*1
× 1000
1 FUNCTIONS
1.6 Alert Output Function
1
35