Endress+Hauser RIA 450 Manual De Instrucciones página 54

Process display
Set point SP:
The set point sets the limit for the operating mode "Trend
monitoring". The prefix sets the direction in which the change is
monitored. Once the measured signal has reached this preset
value the relay is de-energised. The display indicates all
infringed set points.
Hysteresis HYST
Setting up a hysteresis has the effect of setting a difference
between the „On" and „Off" set points. This then avoids
unnecessary switching (hunting) of the alarm relay.
Reset point RESP
This entry sets the size and direction of the measured signal
change in the function "Trend monitoring". If the value of the
signal change per time unit (MW
preset value the relay energises.
The prefix sets the direction of the signal change, rising signal
with MW
Prefix "plus"
52
SP
À Relay de-energised
À Relay de-energised
> MW , falling signal with MW
E A
Dependent on the wiring
either opening or closing
contacts can be used.
On maximum safety the
return switch point is
HYST.
calculated by the set point
minus the hysteresis (SP -
HYST), on minimum safety
from the set point plus the (SP
+ HYST).
- MW / tm) falls below the
E A
< MW
E
Prefix "minus"
.
A