Endress+Hauser RMA 421 - Page 70

6. Applications
6.1 Set point monitoring
In a 10 m high silo the height is to be displayed, a low set point
of 1.5 m and a maximum set point of 8.5 m are to be
monitored. The hysteresis, in order to avoid relay hunting
around the set point, is in both cases to be set at 0.25 m. The
minimum set point is also to have a switch time delay of 10 sec.
Example:
Input signal and display:
- Sensor signal 0-20 mA equals 0-10 m
- Numeric display should show 0.00-10.00 (m)
- Bargraph should show 0.00-10.00 (m)
Set point 1:
- Minimum safety
- Switch point 1.50 (m)
- Hysteresis 0.25 (m)
- Time delay 10 s
Set point 2:
- Maximum safety
- Switch point 8.50 (m)
- Hysteresis 0.25 (m)
- Time delay 0 s
SSetting up:
Menu group Address Value
Analogue input
INPUT Input range RANG
0-20
Display DISPL Decimal point DI DP
Display value:
Range 0%
DI LO
Display value:
Range 100%
DI HI
999,99
0,00
10,00
Set point/fault monitor LIM1 Mode MODE1
Set point SETP1
Hysteresis HYST1
Time delay DELY1
MIN
1,50
0,25
10
Set point/fault monitor LIM2 Mode MODE2
Set point SETP2
Hysteresis HYST2
Time delay DELY2
MAX
8,50
0,25
0
Process transmitter
68