Siemens SITRANS LUT400 Operating Instructions Manual page 92

Set Relays to SERVICE RATIO DUTY BACKUP (SRB)
Parameter
2.7.1.5. Pump Control Mode
Set the Service Ratio for each pump
Parameter
2.7.1.10. Service Ratio Pump 1
2.7.1.11. Service Ratio Pump 2
Set the ON Setpoints
Parameter
2.7.1.6. ON Setpoint Pump 1
2.7.1.8. ON Setpoint Pump 2
Set the OFF Setpoints
Parameter
2.7.1.7. OFF Setpoint Pump 1
2.7.1.9. OFF Setpoint Pump 2
Notes:
• The SITRANS LUT400 will not sacrifice other pumping strategies to ensure that
the service ratio is held true
• If the pump ratios are set to the same value, then the ratio equals 1:1 and all
pumps are used equally (default)
When a pump start is required (ON Setpoint), the pump with the fewest running hours (with
respect to the assigned ratio values) starts.
Conversely, when a pump stop is required (OFF Setpoint), if multiple pumps are running
simultaneously, the pump with the most running hours (as compared to the assigned ratio
values) stops.
Page 84 SITRANS LUT400 (HART) – OPERATING INSTRUCTIONS
Value Description
SRB Sets the control algorithm used to trip the
pump relay to SERVICE RATIO DUTY BACKUP .
Only one pump can run at a time. Pump usage
is based on RUN time rather than last used.
Sample
Description
Value
25 Sets the ratio to: 25% for pump 1, i.e. pump 1
will run 25% of the time.
75 Sets the ratio to: 75% for pump 2, i.e pump 2
will run 75% of the time
Sample
Description
Value
1.3 m Sets the level at which the first pump turns on.
1.2 m Sets the level at which the second pump turns
on.
Sample
Description
Value
0.4 m Sets the level at which the first pump turns off.
0.3 m Sets the level at which the second pump turns
off.
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