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10. Comparison settings
10-4. Hysteresis
This function applies a width to switching from ON to OFF for high limit and low limit judgment.
If the indicator value fluctuates near a comparison value, causing judgment output to chatter between ON and OFF, adjustment of
the hysteresis value can prevent this chattering.
The operation of hysteresis changes as follows according to the Comparison Pattern Setting.
For limit boundary values that are greater than the OK position, it operates in the negative direction. For limit boundary values that
are less than the OK position, it operates in the positive direction.
When the Comparison Pattern Setting is LO/OK/HI, hysteresis activates for the high limit value when an indicator value decreases and
for the low limit and low limit value when an indicator value increases.
OFF
ON
HI
OFF
ON
LO
OFF
ON
HI
OFF
ON
Indicator value
Indicator value
Time
Time
High limit value
High limit value
Low limit value
Judgment output
when hysteresais disabled
Judgment output
when hysteresis enabled
High limit value
Judgment output
Judgment output
Hysteresis
Hysteresis
Hysteresis
Judgment output conditions (when Comparison Output Pattern is set to Standard Output)
Judgment
output
Status
Condition
ATTENTION
Set the hysteresis setting value so that it meets the
following condition.
Low limit value < (high limit value − hysteresis setting
value)
NOTE
o
The same hysteresis width setting is used with high
limit and low limit values.
o
If set to “0”, hysteresis will be disabled.
HI
OFF
w
ON
High limit value < indicator value
ON
w
OFF
Indicator value ≤ (high limit value − hysteresis
setting value)
LO
OFF
w
ON
Indicator value < low limit value
ON
w
OFF
(Low limit value + hysteresis setting value) ≤
indicator value
