System Of Units - Siemens SINAMICS G115D Operating Instructions Manual

6.12.2

System of units

Some physical units depend on the system of units selected (SI or US), for example the power
[kW or hp] or the torque [Nm or lbf ft]. You can select in which system of units the converter
represents its physical values.
Options when selecting the system of units
The following options apply when selecting the system of units:
• p0505 = 1: System of units SI (factory setting)
Torque [Nm], power [kW], temperature [°C or K]
• p0505 = 2: Referred system of units/SI
Represented as [%]
• p0505 = 3: US system of units
Torque [lbf ft], power [hp], temperature [°F]
• p0505 = 4: System of units, referred/US
Represented as [%]
Special features
The values for p0505 = 2 and for p0505 = 4 - represented in the converter - are identical.
However, the reference to SI or US units is required for internal calculations and to output
physical variables.
For variables, which cannot be represented as [%], then the following applies:
p0505 = 1 ≙ p0505 = 2 and p0505 = 3 ≙ p0505 = 4.
In the case of variables whose units are identical in the SI system and US system, and which
can be displayed as a percentage, the following applies:
p0505 = 1 ≙ p0505 = 3 and p0505 = 2 ≙ p0505 = 4.
Reference variables
There is a reference variable in the converter for most parameters with physical units. When
the referred representation [%] is set, then the converter scales the physical variables based
on the particular reference variable.
When the reference variable changes, then the significance of the scaled value also changes.
Example:
• Reference speed = 1500 rpm → fixed speed = 80 % ≙ 1200 rpm
• Reference speed = 3000 rpm → fixed speed = 80 % ≙ 2400 rpm
For each parameter you can find the associated reference variable for scaling in the List
Manual. Example: r0065 is scaled with reference variable p2000.
If scaling is not specified in the List Manual, then the converter always represents/displays the
parameter unscaled (not normalized).
SINAMICS G115D distributed drive
Operating Instructions, 09/2020, FW V4.7 SP13, A5E48681219B
Advanced commissioning
6.12 Selecting physical units
185