Energy-Saving Display - Siemens SINAMICS G120 Original Instructions Manual

Setting functions
8.7 Application-specific functions
8.7.2

Energy-saving display

Background
Conventionally-controlled fluid flow machines control the flow rate using valves or throttles.
In so doing, the drive operates constantly at the rated speed. The efficiency of the system
decreases if the flow rate is reduced using valves or throttles. The efficiency is the lowest
when valves or throttles are completely closed. Further, undesirable effects can occur, e.g.
the formation of vapor bubbles in liquids (cavitation) or the temperature rise of the medium
being pumped increases.
The inverter controls the flow rate or the pressure by varying the speed of the fluid flow
machine. As a consequence, over its complete operating range, a fluid-flow machine
operates close to its maximum efficiency – and especially in partial load operation, uses less
energy than for valve and throttle-based controls.
Function
The energy-saving display calculates the energy saved when operating fluid-flow machines,
e.g. centrifugal pumps, fans, radial and axial compressors. The energy-saving display
compares inverter operation with direct on line operation and throttle control.
The inverter indicates the energy saved in parameter r0041 in kWh, referred to the last
100 operating hours.
For less than 100 operating hours, the inverter interpolates the energy saving to
100 operating hours.
The inverter calculates the energy-saving based on the operating characteristic that has
been saved.
Table 8- 25
Power
Speed
If you require a precise value for the energy saving, then you must adapt the operating
characteristic set in the factory.
Additional parameters for the energy usage display:
r0039[0]: Energy usage since the last reset
r0039[1]: Energy drawn since the last reset
r0039[2]: Energy fed back since the last reset
p0040: Parameter to reset parameters r0039 and r0041.
r0041: Displays the saved energy since the last reset, referred to the operating
characteristic, defined by parameters p3320 ...p3329.
272
Operating characteristic set in the factory
Point 1 Point 2
p3320 = 25% p3322 = 50%
p3321 = 0% p3323 = 25%
Point 3 Point 4
p3324 = 77% p3326 = 92%
p3325 = 50% p3327 = 75%
Inverter with CU230P-2 Control Units
Operating Instructions, 11/2013, FW V4.6.6, A5E02430659B AG
Point 5
p3328 = 100%
p3329 = 100%