Applications - Endress+Hauser RTA421 Mode D'emploi

7. Applications

7.1 Alarm set point monitor
The level in a 10 m high silo is to be displayed front end and
also monitored for a minimum level of 2 m (20%) and a
maximum level of 8 m (80%). The hysteresis in order to avoid
unnecessary relay switching in the area of the set points is 2%
in both cases. The minimum level must also be set with a 10
sec time delay.
Example:
Input signal and display:
- Sensor signal 0-20 mA equals 0-10 m
Set point 1:
- Minimum monitoring
- Switch threshold 20% (2 m)
- Hysteresis 2%
- Time delay 10 s
Set point 2:
- Maximum monitoring
- Switch threshold 80% (8 m)
- Hysteresis 2%
- Time delay 0 s
Setting up:
Menu group
Analogue input
Set point monitor
LI 1
Set point monitor
LI 2
Address
Input range
RA NG
Operating mode
MO
Switch threshold
SP 1
Hysteresis
HY 1
Time delay
DL Y1
Operating mode
MO 2
Switch threshold
SP 2
Hysteresis
HY 2
Time delay
DL Y2
Contactor
SP 2
SP 1
Set up value
0-20
MI N
20
2
10
MA X
80
2
0
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